Solve 12x − 15 = −111

The solution of 12x − 15 = −111 is x = -8.

12x - 15 = -111\ \Rightarrow\ x = -8

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The lines y = 12x − 15 and y = -111 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 subtraction, then the multiplication.
$12x - 15 = -111$
2
Add 15 to both sides:
$12x - 15 + 15 = -111 + 15 \ \Rightarrow\ 12x = -96$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{-96}{12} \ \Rightarrow\ x = -8$
4
Check: put x = -8 back into the equation.
$12\cdot(-8) - 15 = -96 - 15 = -111 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 15 = -111\ \Rightarrow\ x = -8 \]
\[ 12x - 15 = -111 \]
\[ 12x - 15 + 15 = -111 + 15 \ \Rightarrow\ 12x = -96 \]
\[ \frac{12x}{12} = \frac{-96}{12} \ \Rightarrow\ x = -8 \]
\[ 12\cdot(-8) - 15 = -96 - 15 = -111 \checkmark \]

Trying values of x in 12x − 15 = −111

x	12x − 15	Equals -111?
-10	-135	no
-9	-123	no
-8	-111	yes
-7	-99	no
-6	-87	no

Questions

What is x in 12x − 15 = −111?

The solution of 12x − 15 = −111 is x = -8.

How do you solve 12x − 15 = −111?

Add 15 to both sides to get 12x = -96, then divide both sides by 12 to get x = -8.

How do I check the answer?

Replace x by -8: 12(-8) − 15 = -111, which is -111.

Solve 12x − 15 = −111

How to work it out

Trying values of x in 12x − 15 = −111

Questions

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