Solve 12x − 7 = −55

The solution of 12x − 7 = −55 is x = -4.

12x - 7 = -55\ \Rightarrow\ x = -4

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The lines y = 12x − 7 and y = -55 meet at x = -4. 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.
$12x - 7 = -55$
2
Add 7 to both sides:
$12x - 7 + 7 = -55 + 7 \ \Rightarrow\ 12x = -48$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{-48}{12} \ \Rightarrow\ x = -4$
4
Check: put x = -4 back into the equation.
$12\cdot(-4) - 7 = -48 - 7 = -55 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 7 = -55\ \Rightarrow\ x = -4 \]
\[ 12x - 7 = -55 \]
\[ 12x - 7 + 7 = -55 + 7 \ \Rightarrow\ 12x = -48 \]
\[ \frac{12x}{12} = \frac{-48}{12} \ \Rightarrow\ x = -4 \]
\[ 12\cdot(-4) - 7 = -48 - 7 = -55 \checkmark \]

Trying values of x in 12x − 7 = −55

x	12x − 7	Equals -55?
-6	-79	no
-5	-67	no
-4	-55	yes
-3	-43	no
-2	-31	no

Questions

What is x in 12x − 7 = −55?

The solution of 12x − 7 = −55 is x = -4.

How do you solve 12x − 7 = −55?

Add 7 to both sides to get 12x = -48, then divide both sides by 12 to get x = -4.

How do I check the answer?

Replace x by -4: 12(-4) − 7 = -55, which is -55.

Solve 12x − 7 = −55

How to work it out

Trying values of x in 12x − 7 = −55

Questions

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