Solve for r
r=-\frac{u}{2}
Solve for u
u=-2r
Share
Copied to clipboard
2r+u+r=r
Combine r and r to get 2r.
3r+u=r
Combine 2r and r to get 3r.
3r+u-r=0
Subtract r from both sides.
2r+u=0
Combine 3r and -r to get 2r.
2r=-u
Subtract u from both sides. Anything subtracted from zero gives its negation.
\frac{2r}{2}=-\frac{u}{2}
Divide both sides by 2.
r=-\frac{u}{2}
Dividing by 2 undoes the multiplication by 2.
2r+u+r=r
Combine r and r to get 2r.
3r+u=r
Combine 2r and r to get 3r.
u=r-3r
Subtract 3r from both sides.
u=-2r
Combine r and -3r to get -2r.
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}