Solve 11x + 7 = −81

The solution of 11x + 7 = −81 is x = -8.

11x + 7 = -81\ \Rightarrow\ x = -8

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The lines y = 11x + 7 and y = -81 meet at x = -8. The solution of the equation is the x-coordinate of the point where the two sides are equal.

How to work it out

1
The goal is to get x alone. Undo the operations in the opposite order: first the addition, then the multiplication.
$11x + 7 = -81$
2
Subtract 7 from both sides:
$11x + 7 - 7 = -81 - 7 \ \Rightarrow\ 11x = -88$
3
Divide both sides by 11:
$\frac{11x}{11} = \frac{-88}{11} \ \Rightarrow\ x = -8$
4
Check: put x = -8 back into the equation.
$11\cdot(-8) + 7 = -88 + 7 = -81 \checkmark$

LaTeX source of the formulas on this page

\[ 11x + 7 = -81\ \Rightarrow\ x = -8 \]
\[ 11x + 7 = -81 \]
\[ 11x + 7 - 7 = -81 - 7 \ \Rightarrow\ 11x = -88 \]
\[ \frac{11x}{11} = \frac{-88}{11} \ \Rightarrow\ x = -8 \]
\[ 11\cdot(-8) + 7 = -88 + 7 = -81 \checkmark \]

Trying values of x in 11x + 7 = −81

x	11x + 7	Equals -81?
-10	-103	no
-9	-92	no
-8	-81	yes
-7	-70	no
-6	-59	no

Questions

What is x in 11x + 7 = −81?

The solution of 11x + 7 = −81 is x = -8.

How do you solve 11x + 7 = −81?

Subtract 7 from both sides to get 11x = -88, then divide both sides by 11 to get x = -8.

How do I check the answer?

Replace x by -8: 11(-8) + 7 = -81, which is -81.

Solve 11x + 7 = −81

How to work it out

Trying values of x in 11x + 7 = −81

Questions

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