Solve 12x − 7 = −91

The solution of 12x − 7 = −91 is x = -7.

12x - 7 = -91\ \Rightarrow\ x = -7

Explain it step by step in chat Make a short video of it

The lines y = 12x − 7 and y = -91 meet at x = -7. 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.
$12x - 7 = -91$
2
Add 7 to both sides:
$12x - 7 + 7 = -91 + 7 \ \Rightarrow\ 12x = -84$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{-84}{12} \ \Rightarrow\ x = -7$
4
Check: put x = -7 back into the equation.
$12\cdot(-7) - 7 = -84 - 7 = -91 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 7 = -91\ \Rightarrow\ x = -7 \]
\[ 12x - 7 = -91 \]
\[ 12x - 7 + 7 = -91 + 7 \ \Rightarrow\ 12x = -84 \]
\[ \frac{12x}{12} = \frac{-84}{12} \ \Rightarrow\ x = -7 \]
\[ 12\cdot(-7) - 7 = -84 - 7 = -91 \checkmark \]

Trying values of x in 12x − 7 = −91

x	12x − 7	Equals -91?
-9	-115	no
-8	-103	no
-7	-91	yes
-6	-79	no
-5	-67	no

Questions

What is x in 12x − 7 = −91?

The solution of 12x − 7 = −91 is x = -7.

How do you solve 12x − 7 = −91?

Add 7 to both sides to get 12x = -84, then divide both sides by 12 to get x = -7.

How do I check the answer?

Replace x by -7: 12(-7) − 7 = -91, which is -91.

Solve 12x − 7 = −91

How to work it out

Trying values of x in 12x − 7 = −91

Questions

Similar equations