Solve for x
x = -\frac{14}{5} = -2\frac{4}{5} = -2.8
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2x-21-7x=-7
Subtract 7x from both sides.
-5x-21=-7
Combine 2x and -7x to get -5x.
-5x=-7+21
Add 21 to both sides.
-5x=14
Add -7 and 21 to get 14.
x=\frac{14}{-5}
Divide both sides by -5.
x=-\frac{14}{5}
Fraction \frac{14}{-5} can be rewritten as -\frac{14}{5} by extracting the negative sign.
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}