How do we solve for all values of $x$?
$begingroup$
Suppose
$$(x^2 - 5)^{8} (x+1)^{-16} = 1$$
How do we solve for all values of $x$?
I think we can equate the bases to $1$ in order to get $$1 times 1 = 1$$
$$x^2-5 = 1, x^2-5=-1$$
or
$$x + 1 = 1, x + 1 = -1$$
Could you assist me with this?
algebra-precalculus
$endgroup$
add a comment |
$begingroup$
Suppose
$$(x^2 - 5)^{8} (x+1)^{-16} = 1$$
How do we solve for all values of $x$?
I think we can equate the bases to $1$ in order to get $$1 times 1 = 1$$
$$x^2-5 = 1, x^2-5=-1$$
or
$$x + 1 = 1, x + 1 = -1$$
Could you assist me with this?
algebra-precalculus
$endgroup$
add a comment |
$begingroup$
Suppose
$$(x^2 - 5)^{8} (x+1)^{-16} = 1$$
How do we solve for all values of $x$?
I think we can equate the bases to $1$ in order to get $$1 times 1 = 1$$
$$x^2-5 = 1, x^2-5=-1$$
or
$$x + 1 = 1, x + 1 = -1$$
Could you assist me with this?
algebra-precalculus
$endgroup$
Suppose
$$(x^2 - 5)^{8} (x+1)^{-16} = 1$$
How do we solve for all values of $x$?
I think we can equate the bases to $1$ in order to get $$1 times 1 = 1$$
$$x^2-5 = 1, x^2-5=-1$$
or
$$x + 1 = 1, x + 1 = -1$$
Could you assist me with this?
algebra-precalculus
algebra-precalculus
asked Dec 18 '18 at 21:35
EnzoEnzo
19917
19917
add a comment |
add a comment |
3 Answers
3
active
oldest
votes
$begingroup$
$(x^2 - 5)^{8} (x+1)^{-16} = 1$ means
$(x^2 - 5)^{8} = (x+1)^{16}$.
Assuming you only want real and not complex answers then
$ sqrt[8]{(x^2 - 5)^{8}} = sqrt[8]{(x+1)^{16}}$
$|x^2 - 5| = (x+1)^2$
or either A) $x^2 - 5 = (x+1)^2$ or B) $5- x^2 = (x+1)^2$
A) $x^2 - 5 = x^2 + 2x + 1$
$2x = -6$
$x = -3$.
Verification: $(x^2 - 5)^8(x+1)^{-16}=frac{(9-5)^8}{(-2)^{16}}= frac {4^8}{2^{16}}=frac {2^{16}}{2^{16}} = 1$.
B)$5- x^2 = (x+1)^2$
$5-x^2 = x^2 + 2x + 1$
$2x^2 + 2x -4 = 0$
$x^2 + x -2 = 0$
$(x +2)(x-1) = 0$ so either C) $x+2 = 0$ and $x=-2$ or $x-1=0$ and $x = 1$.
So solutions are $x = -3; x = -2;$ or $x = 1$.
Verification:
$(x^2 - 5)^8(x+1)^{-16} = frac {(4-5)^8}{(-2 + 1)^{16}}= frac {(-1)^8}{(-1)^{16}} = frac 11 = 1$. so $x = -2$ is a solution.
$(x^2 - 5)^8(x+1)^{-16} = frac {(1-5)^8}{(1 + 1)^{16}}= frac {(-4)^8}{(2)^{16}} = frac {4^8}{4^8} = 1$. so $x = 1$ is a solution.
$endgroup$
add a comment |
$begingroup$
We have $(x^2-5)^8(x+1)^{-16}=1$, so $left(frac{x^2-5}{(x+1)^2}right)^8=1$, so $frac{x^2-5}{(x+1)^2}$ is an $8$'th root of unity. Assuming you need to solve over the reals, we get $frac{x^2-5}{(x+1)^2}in{-1,1}$. Fixing for $-1$ or $1$, you can multiply both sides by $(x+1)^2$ to get a quadratic equation.
$endgroup$
add a comment |
$begingroup$
$(x^2-5)^8=(x+1)^{16}$
So
$[(x^2-5)^4-(x+1)^8] [(x^2-5)^4+(x+1)^8]=0$
If and only if
$[(x^2-5)^4-(x+1)^8]=0$
If and only if
$[(x^2-5)^2-(x+1)^4]=0$
If and only if
$[(x^2-5)-(x+1)^2] [(x^2-5)+(x+1)^2]=0$
So
$[-2x-6][2x^2+2x-4]=0$
$endgroup$
add a comment |
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3 Answers
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active
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3 Answers
3
active
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votes
$begingroup$
$(x^2 - 5)^{8} (x+1)^{-16} = 1$ means
$(x^2 - 5)^{8} = (x+1)^{16}$.
Assuming you only want real and not complex answers then
$ sqrt[8]{(x^2 - 5)^{8}} = sqrt[8]{(x+1)^{16}}$
$|x^2 - 5| = (x+1)^2$
or either A) $x^2 - 5 = (x+1)^2$ or B) $5- x^2 = (x+1)^2$
A) $x^2 - 5 = x^2 + 2x + 1$
$2x = -6$
$x = -3$.
Verification: $(x^2 - 5)^8(x+1)^{-16}=frac{(9-5)^8}{(-2)^{16}}= frac {4^8}{2^{16}}=frac {2^{16}}{2^{16}} = 1$.
B)$5- x^2 = (x+1)^2$
$5-x^2 = x^2 + 2x + 1$
$2x^2 + 2x -4 = 0$
$x^2 + x -2 = 0$
$(x +2)(x-1) = 0$ so either C) $x+2 = 0$ and $x=-2$ or $x-1=0$ and $x = 1$.
So solutions are $x = -3; x = -2;$ or $x = 1$.
Verification:
$(x^2 - 5)^8(x+1)^{-16} = frac {(4-5)^8}{(-2 + 1)^{16}}= frac {(-1)^8}{(-1)^{16}} = frac 11 = 1$. so $x = -2$ is a solution.
$(x^2 - 5)^8(x+1)^{-16} = frac {(1-5)^8}{(1 + 1)^{16}}= frac {(-4)^8}{(2)^{16}} = frac {4^8}{4^8} = 1$. so $x = 1$ is a solution.
$endgroup$
add a comment |
$begingroup$
$(x^2 - 5)^{8} (x+1)^{-16} = 1$ means
$(x^2 - 5)^{8} = (x+1)^{16}$.
Assuming you only want real and not complex answers then
$ sqrt[8]{(x^2 - 5)^{8}} = sqrt[8]{(x+1)^{16}}$
$|x^2 - 5| = (x+1)^2$
or either A) $x^2 - 5 = (x+1)^2$ or B) $5- x^2 = (x+1)^2$
A) $x^2 - 5 = x^2 + 2x + 1$
$2x = -6$
$x = -3$.
Verification: $(x^2 - 5)^8(x+1)^{-16}=frac{(9-5)^8}{(-2)^{16}}= frac {4^8}{2^{16}}=frac {2^{16}}{2^{16}} = 1$.
B)$5- x^2 = (x+1)^2$
$5-x^2 = x^2 + 2x + 1$
$2x^2 + 2x -4 = 0$
$x^2 + x -2 = 0$
$(x +2)(x-1) = 0$ so either C) $x+2 = 0$ and $x=-2$ or $x-1=0$ and $x = 1$.
So solutions are $x = -3; x = -2;$ or $x = 1$.
Verification:
$(x^2 - 5)^8(x+1)^{-16} = frac {(4-5)^8}{(-2 + 1)^{16}}= frac {(-1)^8}{(-1)^{16}} = frac 11 = 1$. so $x = -2$ is a solution.
$(x^2 - 5)^8(x+1)^{-16} = frac {(1-5)^8}{(1 + 1)^{16}}= frac {(-4)^8}{(2)^{16}} = frac {4^8}{4^8} = 1$. so $x = 1$ is a solution.
$endgroup$
add a comment |
$begingroup$
$(x^2 - 5)^{8} (x+1)^{-16} = 1$ means
$(x^2 - 5)^{8} = (x+1)^{16}$.
Assuming you only want real and not complex answers then
$ sqrt[8]{(x^2 - 5)^{8}} = sqrt[8]{(x+1)^{16}}$
$|x^2 - 5| = (x+1)^2$
or either A) $x^2 - 5 = (x+1)^2$ or B) $5- x^2 = (x+1)^2$
A) $x^2 - 5 = x^2 + 2x + 1$
$2x = -6$
$x = -3$.
Verification: $(x^2 - 5)^8(x+1)^{-16}=frac{(9-5)^8}{(-2)^{16}}= frac {4^8}{2^{16}}=frac {2^{16}}{2^{16}} = 1$.
B)$5- x^2 = (x+1)^2$
$5-x^2 = x^2 + 2x + 1$
$2x^2 + 2x -4 = 0$
$x^2 + x -2 = 0$
$(x +2)(x-1) = 0$ so either C) $x+2 = 0$ and $x=-2$ or $x-1=0$ and $x = 1$.
So solutions are $x = -3; x = -2;$ or $x = 1$.
Verification:
$(x^2 - 5)^8(x+1)^{-16} = frac {(4-5)^8}{(-2 + 1)^{16}}= frac {(-1)^8}{(-1)^{16}} = frac 11 = 1$. so $x = -2$ is a solution.
$(x^2 - 5)^8(x+1)^{-16} = frac {(1-5)^8}{(1 + 1)^{16}}= frac {(-4)^8}{(2)^{16}} = frac {4^8}{4^8} = 1$. so $x = 1$ is a solution.
$endgroup$
$(x^2 - 5)^{8} (x+1)^{-16} = 1$ means
$(x^2 - 5)^{8} = (x+1)^{16}$.
Assuming you only want real and not complex answers then
$ sqrt[8]{(x^2 - 5)^{8}} = sqrt[8]{(x+1)^{16}}$
$|x^2 - 5| = (x+1)^2$
or either A) $x^2 - 5 = (x+1)^2$ or B) $5- x^2 = (x+1)^2$
A) $x^2 - 5 = x^2 + 2x + 1$
$2x = -6$
$x = -3$.
Verification: $(x^2 - 5)^8(x+1)^{-16}=frac{(9-5)^8}{(-2)^{16}}= frac {4^8}{2^{16}}=frac {2^{16}}{2^{16}} = 1$.
B)$5- x^2 = (x+1)^2$
$5-x^2 = x^2 + 2x + 1$
$2x^2 + 2x -4 = 0$
$x^2 + x -2 = 0$
$(x +2)(x-1) = 0$ so either C) $x+2 = 0$ and $x=-2$ or $x-1=0$ and $x = 1$.
So solutions are $x = -3; x = -2;$ or $x = 1$.
Verification:
$(x^2 - 5)^8(x+1)^{-16} = frac {(4-5)^8}{(-2 + 1)^{16}}= frac {(-1)^8}{(-1)^{16}} = frac 11 = 1$. so $x = -2$ is a solution.
$(x^2 - 5)^8(x+1)^{-16} = frac {(1-5)^8}{(1 + 1)^{16}}= frac {(-4)^8}{(2)^{16}} = frac {4^8}{4^8} = 1$. so $x = 1$ is a solution.
answered Dec 18 '18 at 21:56
fleabloodfleablood
72.8k22788
72.8k22788
add a comment |
add a comment |
$begingroup$
We have $(x^2-5)^8(x+1)^{-16}=1$, so $left(frac{x^2-5}{(x+1)^2}right)^8=1$, so $frac{x^2-5}{(x+1)^2}$ is an $8$'th root of unity. Assuming you need to solve over the reals, we get $frac{x^2-5}{(x+1)^2}in{-1,1}$. Fixing for $-1$ or $1$, you can multiply both sides by $(x+1)^2$ to get a quadratic equation.
$endgroup$
add a comment |
$begingroup$
We have $(x^2-5)^8(x+1)^{-16}=1$, so $left(frac{x^2-5}{(x+1)^2}right)^8=1$, so $frac{x^2-5}{(x+1)^2}$ is an $8$'th root of unity. Assuming you need to solve over the reals, we get $frac{x^2-5}{(x+1)^2}in{-1,1}$. Fixing for $-1$ or $1$, you can multiply both sides by $(x+1)^2$ to get a quadratic equation.
$endgroup$
add a comment |
$begingroup$
We have $(x^2-5)^8(x+1)^{-16}=1$, so $left(frac{x^2-5}{(x+1)^2}right)^8=1$, so $frac{x^2-5}{(x+1)^2}$ is an $8$'th root of unity. Assuming you need to solve over the reals, we get $frac{x^2-5}{(x+1)^2}in{-1,1}$. Fixing for $-1$ or $1$, you can multiply both sides by $(x+1)^2$ to get a quadratic equation.
$endgroup$
We have $(x^2-5)^8(x+1)^{-16}=1$, so $left(frac{x^2-5}{(x+1)^2}right)^8=1$, so $frac{x^2-5}{(x+1)^2}$ is an $8$'th root of unity. Assuming you need to solve over the reals, we get $frac{x^2-5}{(x+1)^2}in{-1,1}$. Fixing for $-1$ or $1$, you can multiply both sides by $(x+1)^2$ to get a quadratic equation.
edited Dec 18 '18 at 22:46
answered Dec 18 '18 at 21:47
SmileyCraftSmileyCraft
3,749519
3,749519
add a comment |
add a comment |
$begingroup$
$(x^2-5)^8=(x+1)^{16}$
So
$[(x^2-5)^4-(x+1)^8] [(x^2-5)^4+(x+1)^8]=0$
If and only if
$[(x^2-5)^4-(x+1)^8]=0$
If and only if
$[(x^2-5)^2-(x+1)^4]=0$
If and only if
$[(x^2-5)-(x+1)^2] [(x^2-5)+(x+1)^2]=0$
So
$[-2x-6][2x^2+2x-4]=0$
$endgroup$
add a comment |
$begingroup$
$(x^2-5)^8=(x+1)^{16}$
So
$[(x^2-5)^4-(x+1)^8] [(x^2-5)^4+(x+1)^8]=0$
If and only if
$[(x^2-5)^4-(x+1)^8]=0$
If and only if
$[(x^2-5)^2-(x+1)^4]=0$
If and only if
$[(x^2-5)-(x+1)^2] [(x^2-5)+(x+1)^2]=0$
So
$[-2x-6][2x^2+2x-4]=0$
$endgroup$
add a comment |
$begingroup$
$(x^2-5)^8=(x+1)^{16}$
So
$[(x^2-5)^4-(x+1)^8] [(x^2-5)^4+(x+1)^8]=0$
If and only if
$[(x^2-5)^4-(x+1)^8]=0$
If and only if
$[(x^2-5)^2-(x+1)^4]=0$
If and only if
$[(x^2-5)-(x+1)^2] [(x^2-5)+(x+1)^2]=0$
So
$[-2x-6][2x^2+2x-4]=0$
$endgroup$
$(x^2-5)^8=(x+1)^{16}$
So
$[(x^2-5)^4-(x+1)^8] [(x^2-5)^4+(x+1)^8]=0$
If and only if
$[(x^2-5)^4-(x+1)^8]=0$
If and only if
$[(x^2-5)^2-(x+1)^4]=0$
If and only if
$[(x^2-5)-(x+1)^2] [(x^2-5)+(x+1)^2]=0$
So
$[-2x-6][2x^2+2x-4]=0$
answered Dec 18 '18 at 21:40
Federico FalluccaFederico Fallucca
2,280210
2,280210
add a comment |
add a comment |
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