Solve for a
a=b+4
Solve for b
b=a-4
Share
Copied to clipboard
a+b-2a=-4
Subtract 2a from both sides.
-a+b=-4
Combine a and -2a to get -a.
-a=-4-b
Subtract b from both sides.
-a=-b-4
The equation is in standard form.
\frac{-a}{-1}=\frac{-b-4}{-1}
Divide both sides by -1.
a=\frac{-b-4}{-1}
Dividing by -1 undoes the multiplication by -1.
a=b+4
Divide -4-b by -1.
b=2a-4-a
Subtract a from both sides.
b=a-4
Combine 2a and -a to get a.
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}