Solve 8x − 12 = 140

The solution of 8x − 12 = 140 is x = 19.

8x - 12 = 140\ \Rightarrow\ x = 19

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The lines y = 8x − 12 and y = 140 meet at x = 19. 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.
$8x - 12 = 140$
2
Add 12 to both sides:
$8x - 12 + 12 = 140 + 12 \ \Rightarrow\ 8x = 152$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{152}{8} \ \Rightarrow\ x = 19$
4
Check: put x = 19 back into the equation.
$8\cdot19 - 12 = 152 - 12 = 140 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 12 = 140\ \Rightarrow\ x = 19 \]
\[ 8x - 12 = 140 \]
\[ 8x - 12 + 12 = 140 + 12 \ \Rightarrow\ 8x = 152 \]
\[ \frac{8x}{8} = \frac{152}{8} \ \Rightarrow\ x = 19 \]
\[ 8\cdot19 - 12 = 152 - 12 = 140 \checkmark \]

Trying values of x in 8x − 12 = 140

x	8x − 12	Equals 140?
17	124	no
18	132	no
19	140	yes
20	148	no
21	156	no

Questions

What is x in 8x − 12 = 140?

The solution of 8x − 12 = 140 is x = 19.

How do you solve 8x − 12 = 140?

Add 12 to both sides to get 8x = 152, then divide both sides by 8 to get x = 19.

How do I check the answer?

Replace x by 19: 8(19) − 12 = 140, which is 140.

Solve 8x − 12 = 140

How to work it out

Trying values of x in 8x − 12 = 140

Questions

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