Solve 11x + 9 = −79

The solution of 11x + 9 = −79 is x = -8.

11x + 9 = -79\ \Rightarrow\ x = -8

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The lines y = 11x + 9 and y = -79 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.
$11x + 9 = -79$
2
Subtract 9 from both sides:
$11x + 9 - 9 = -79 - 9 \ \Rightarrow\ 11x = -88$
3
Divide both sides by 11:
$\frac{11x}{11} = \frac{-88}{11} \ \Rightarrow\ x = -8$
4
Check: put x = -8 back into the equation.
$11\cdot(-8) + 9 = -88 + 9 = -79 \checkmark$

LaTeX source of the formulas on this page

\[ 11x + 9 = -79\ \Rightarrow\ x = -8 \]
\[ 11x + 9 = -79 \]
\[ 11x + 9 - 9 = -79 - 9 \ \Rightarrow\ 11x = -88 \]
\[ \frac{11x}{11} = \frac{-88}{11} \ \Rightarrow\ x = -8 \]
\[ 11\cdot(-8) + 9 = -88 + 9 = -79 \checkmark \]

Trying values of x in 11x + 9 = −79

x	11x + 9	Equals -79?
-10	-101	no
-9	-90	no
-8	-79	yes
-7	-68	no
-6	-57	no

Questions

What is x in 11x + 9 = −79?

The solution of 11x + 9 = −79 is x = -8.

How do you solve 11x + 9 = −79?

Subtract 9 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) + 9 = -79, which is -79.

Solve 11x + 9 = −79

How to work it out

Trying values of x in 11x + 9 = −79

Questions

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