Solve for x
x=7
Graph
Share
Copied to clipboard
9+16+8\left(-\frac{x}{4}\right)+\left(-\frac{x}{4}\right)^{2}=\left(8-\frac{x}{4}\right)^{2}-25
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(4-\frac{x}{4}\right)^{2}.
9+16-2x+\left(-\frac{x}{4}\right)^{2}=\left(8-\frac{x}{4}\right)^{2}-25
Cancel out 4, the greatest common factor in 8 and 4.
9+16-2x+\left(\frac{x}{4}\right)^{2}=\left(8-\frac{x}{4}\right)^{2}-25
Calculate -\frac{x}{4} to the power of 2 and get \left(\frac{x}{4}\right)^{2}.
25-2x+\left(\frac{x}{4}\right)^{2}=\left(8-\frac{x}{4}\right)^{2}-25
Add 9 and 16 to get 25.
25-2x+\frac{x^{2}}{4^{2}}=\left(8-\frac{x}{4}\right)^{2}-25
To raise \frac{x}{4} to a power, raise both numerator and denominator to the power and then divide.
\frac{\left(25-2x\right)\times 4^{2}}{4^{2}}+\frac{x^{2}}{4^{2}}=\left(8-\frac{x}{4}\right)^{2}-25
To add or subtract expressions, expand them to make their denominators the same. Multiply 25-2x times \frac{4^{2}}{4^{2}}.
\frac{\left(25-2x\right)\times 4^{2}+x^{2}}{4^{2}}=\left(8-\frac{x}{4}\right)^{2}-25
Since \frac{\left(25-2x\right)\times 4^{2}}{4^{2}} and \frac{x^{2}}{4^{2}} have the same denominator, add them by adding their numerators.
\frac{400-32x+x^{2}}{4^{2}}=\left(8-\frac{x}{4}\right)^{2}-25
Do the multiplications in \left(25-2x\right)\times 4^{2}+x^{2}.
\frac{400-32x+x^{2}}{4^{2}}=64+16\left(-\frac{x}{4}\right)+\left(-\frac{x}{4}\right)^{2}-25
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(8-\frac{x}{4}\right)^{2}.
\frac{400-32x+x^{2}}{4^{2}}=64-4x+\left(-\frac{x}{4}\right)^{2}-25
Cancel out 4, the greatest common factor in 16 and 4.
\frac{400-32x+x^{2}}{4^{2}}=64-4x+\left(\frac{x}{4}\right)^{2}-25
Calculate -\frac{x}{4} to the power of 2 and get \left(\frac{x}{4}\right)^{2}.
\frac{400-32x+x^{2}}{4^{2}}=64-4x+\frac{x^{2}}{4^{2}}-25
To raise \frac{x}{4} to a power, raise both numerator and denominator to the power and then divide.
\frac{400-32x+x^{2}}{4^{2}}=39-4x+\frac{x^{2}}{4^{2}}
Subtract 25 from 64 to get 39.
\frac{400-32x+x^{2}}{4^{2}}=39-4x+\frac{x^{2}}{16}
Calculate 4 to the power of 2 and get 16.
\frac{400-32x+x^{2}}{16}=39-4x+\frac{x^{2}}{16}
Calculate 4 to the power of 2 and get 16.
25-2x+\frac{1}{16}x^{2}=39-4x+\frac{x^{2}}{16}
Divide each term of 400-32x+x^{2} by 16 to get 25-2x+\frac{1}{16}x^{2}.
25-2x+\frac{1}{16}x^{2}+4x=39+\frac{x^{2}}{16}
Add 4x to both sides.
25+2x+\frac{1}{16}x^{2}=39+\frac{x^{2}}{16}
Combine -2x and 4x to get 2x.
25+2x+\frac{1}{16}x^{2}-\frac{x^{2}}{16}=39
Subtract \frac{x^{2}}{16} from both sides.
25+2x=39
Combine \frac{1}{16}x^{2} and -\frac{x^{2}}{16} to get 0.
2x=39-25
Subtract 25 from both sides.
2x=14
Subtract 25 from 39 to get 14.
x=\frac{14}{2}
Divide both sides by 2.
x=7
Divide 14 by 2 to get 7.
Examples
Quadratic equation
{ x } ^ { 2 } - 4 x - 5 = 0
Trigonometry
4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
Arithmetic
699 * 533
Matrix
\left[ \begin{array} { l l } { 2 } & { 3 } \\ { 5 } & { 4 } \end{array} \right] \left[ \begin{array} { l l l } { 2 } & { 0 } & { 3 } \\ { -1 } & { 1 } & { 5 } \end{array} \right]
Simultaneous equation
\left. \begin{cases} { 8x+2y = 46 } \\ { 7x+3y = 47 } \end{cases} \right.
Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}