Solve for r
r = \frac{20}{7} = 2\frac{6}{7} \approx 2.857142857
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r=\frac{4}{7}\times 5
Multiply both sides by 5.
r=\frac{4\times 5}{7}
Express \frac{4}{7}\times 5 as a single fraction.
r=\frac{20}{7}
Multiply 4 and 5 to get 20.
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
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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
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