Solve 6x + 12 = −42

The solution of 6x + 12 = −42 is x = -9.

6x + 12 = -42\ \Rightarrow\ x = -9

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The lines y = 6x + 12 and y = -42 meet at x = -9. 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.
$6x + 12 = -42$
2
Subtract 12 from both sides:
$6x + 12 - 12 = -42 - 12 \ \Rightarrow\ 6x = -54$
3
Divide both sides by 6:
$\frac{6x}{6} = \frac{-54}{6} \ \Rightarrow\ x = -9$
4
Check: put x = -9 back into the equation.
$6\cdot(-9) + 12 = -54 + 12 = -42 \checkmark$

LaTeX source of the formulas on this page

\[ 6x + 12 = -42\ \Rightarrow\ x = -9 \]
\[ 6x + 12 = -42 \]
\[ 6x + 12 - 12 = -42 - 12 \ \Rightarrow\ 6x = -54 \]
\[ \frac{6x}{6} = \frac{-54}{6} \ \Rightarrow\ x = -9 \]
\[ 6\cdot(-9) + 12 = -54 + 12 = -42 \checkmark \]

Trying values of x in 6x + 12 = −42

x	6x + 12	Equals -42?
-11	-54	no
-10	-48	no
-9	-42	yes
-8	-36	no
-7	-30	no

Questions

What is x in 6x + 12 = −42?

The solution of 6x + 12 = −42 is x = -9.

How do you solve 6x + 12 = −42?

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

How do I check the answer?

Replace x by -9: 6(-9) + 12 = -42, which is -42.

Solve 6x + 12 = −42

How to work it out

Trying values of x in 6x + 12 = −42

Questions

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