Solve 12x − 9 = −69

The solution of 12x − 9 = −69 is x = -5.

12x - 9 = -69\ \Rightarrow\ x = -5

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The lines y = 12x − 9 and y = -69 meet at x = -5. 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.
$12x - 9 = -69$
2
Add 9 to both sides:
$12x - 9 + 9 = -69 + 9 \ \Rightarrow\ 12x = -60$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{-60}{12} \ \Rightarrow\ x = -5$
4
Check: put x = -5 back into the equation.
$12\cdot(-5) - 9 = -60 - 9 = -69 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 9 = -69\ \Rightarrow\ x = -5 \]
\[ 12x - 9 = -69 \]
\[ 12x - 9 + 9 = -69 + 9 \ \Rightarrow\ 12x = -60 \]
\[ \frac{12x}{12} = \frac{-60}{12} \ \Rightarrow\ x = -5 \]
\[ 12\cdot(-5) - 9 = -60 - 9 = -69 \checkmark \]

Trying values of x in 12x − 9 = −69

x	12x − 9	Equals -69?
-7	-93	no
-6	-81	no
-5	-69	yes
-4	-57	no
-3	-45	no

Questions

What is x in 12x − 9 = −69?

The solution of 12x − 9 = −69 is x = -5.

How do you solve 12x − 9 = −69?

Add 9 to both sides to get 12x = -60, then divide both sides by 12 to get x = -5.

How do I check the answer?

Replace x by -5: 12(-5) − 9 = -69, which is -69.

Solve 12x − 9 = −69

How to work it out

Trying values of x in 12x − 9 = −69

Questions

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