Solve for k
k=-5
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-40-3\left(-15\right)+k=0
Multiply 4 and -10 to get -40.
-40-\left(-45\right)+k=0
Multiply 3 and -15 to get -45.
-40+45+k=0
The opposite of -45 is 45.
5+k=0
Add -40 and 45 to get 5.
k=-5
Subtract 5 from both sides. Anything subtracted from zero gives its negation.
Examples
Quadratic equation
{ x } ^ { 2 } - 4 x - 5 = 0
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4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
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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
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