Solve 9x − 12 = −66

The solution of 9x − 12 = −66 is x = -6.

9x - 12 = -66\ \Rightarrow\ x = -6

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The lines y = 9x − 12 and y = -66 meet at x = -6. 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 subtraction, then the multiplication.
$9x - 12 = -66$
2
Add 12 to both sides:
$9x - 12 + 12 = -66 + 12 \ \Rightarrow\ 9x = -54$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{-54}{9} \ \Rightarrow\ x = -6$
4
Check: put x = -6 back into the equation.
$9\cdot(-6) - 12 = -54 - 12 = -66 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 12 = -66\ \Rightarrow\ x = -6 \]
\[ 9x - 12 = -66 \]
\[ 9x - 12 + 12 = -66 + 12 \ \Rightarrow\ 9x = -54 \]
\[ \frac{9x}{9} = \frac{-54}{9} \ \Rightarrow\ x = -6 \]
\[ 9\cdot(-6) - 12 = -54 - 12 = -66 \checkmark \]

Trying values of x in 9x − 12 = −66

x	9x − 12	Equals -66?
-8	-84	no
-7	-75	no
-6	-66	yes
-5	-57	no
-4	-48	no

Questions

What is x in 9x − 12 = −66?

The solution of 9x − 12 = −66 is x = -6.

How do you solve 9x − 12 = −66?

Add 12 to both sides to get 9x = -54, then divide both sides by 9 to get x = -6.

How do I check the answer?

Replace x by -6: 9(-6) − 12 = -66, which is -66.

Solve 9x − 12 = −66

How to work it out

Trying values of x in 9x − 12 = −66

Questions

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