Solve for r
r=\frac{1}{15}\approx 0.066666667
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2r\left(\frac{3}{4}-4r\right)=4\left(\frac{r}{4}-\frac{1}{2}\right)\left(\frac{1}{2}-8r\right)
Multiply both sides of the equation by 4, the least common multiple of 2,4.
2r\times \frac{3}{4}-8r^{2}=4\left(\frac{r}{4}-\frac{1}{2}\right)\left(\frac{1}{2}-8r\right)
Use the distributive property to multiply 2r by \frac{3}{4}-4r.
\frac{2\times 3}{4}r-8r^{2}=4\left(\frac{r}{4}-\frac{1}{2}\right)\left(\frac{1}{2}-8r\right)
Express 2\times \frac{3}{4} as a single fraction.
\frac{6}{4}r-8r^{2}=4\left(\frac{r}{4}-\frac{1}{2}\right)\left(\frac{1}{2}-8r\right)
Multiply 2 and 3 to get 6.
\frac{3}{2}r-8r^{2}=4\left(\frac{r}{4}-\frac{1}{2}\right)\left(\frac{1}{2}-8r\right)
Reduce the fraction \frac{6}{4} to lowest terms by extracting and canceling out 2.
\frac{3}{2}r-8r^{2}=4\left(\frac{r}{4}-\frac{2}{4}\right)\left(\frac{1}{2}-8r\right)
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of 4 and 2 is 4. Multiply \frac{1}{2} times \frac{2}{2}.
\frac{3}{2}r-8r^{2}=4\times \frac{r-2}{4}\left(\frac{1}{2}-8r\right)
Since \frac{r}{4} and \frac{2}{4} have the same denominator, subtract them by subtracting their numerators.
\frac{3}{2}r-8r^{2}=\frac{4\left(r-2\right)}{4}\left(\frac{1}{2}-8r\right)
Express 4\times \frac{r-2}{4} as a single fraction.
\frac{3}{2}r-8r^{2}=\left(r-2\right)\left(\frac{1}{2}-8r\right)
Cancel out 4 and 4.
\frac{3}{2}r-8r^{2}=r\times \frac{1}{2}-8r^{2}-2\times \frac{1}{2}+16r
Apply the distributive property by multiplying each term of r-2 by each term of \frac{1}{2}-8r.
\frac{3}{2}r-8r^{2}=r\times \frac{1}{2}-8r^{2}-1+16r
Multiply -2 times \frac{1}{2}.
\frac{3}{2}r-8r^{2}=\frac{33}{2}r-8r^{2}-1
Combine r\times \frac{1}{2} and 16r to get \frac{33}{2}r.
\frac{3}{2}r-8r^{2}-\frac{33}{2}r=-8r^{2}-1
Subtract \frac{33}{2}r from both sides.
-15r-8r^{2}=-8r^{2}-1
Combine \frac{3}{2}r and -\frac{33}{2}r to get -15r.
-15r-8r^{2}+8r^{2}=-1
Add 8r^{2} to both sides.
-15r=-1
Combine -8r^{2} and 8r^{2} to get 0.
r=\frac{-1}{-15}
Divide both sides by -15.
r=\frac{1}{15}
Fraction \frac{-1}{-15} can be simplified to \frac{1}{15} by removing the negative sign from both the numerator and the denominator.
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}