Solve 12x − 1 = 155

The solution of 12x − 1 = 155 is x = 13.

12x - 1 = 155\ \Rightarrow\ x = 13

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The lines y = 12x − 1 and y = 155 meet at x = 13. 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.
$12x - 1 = 155$
2
Add 1 to both sides:
$12x - 1 + 1 = 155 + 1 \ \Rightarrow\ 12x = 156$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{156}{12} \ \Rightarrow\ x = 13$
4
Check: put x = 13 back into the equation.
$12\cdot13 - 1 = 156 - 1 = 155 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 1 = 155\ \Rightarrow\ x = 13 \]
\[ 12x - 1 = 155 \]
\[ 12x - 1 + 1 = 155 + 1 \ \Rightarrow\ 12x = 156 \]
\[ \frac{12x}{12} = \frac{156}{12} \ \Rightarrow\ x = 13 \]
\[ 12\cdot13 - 1 = 156 - 1 = 155 \checkmark \]

Trying values of x in 12x − 1 = 155

x	12x − 1	Equals 155?
11	131	no
12	143	no
13	155	yes
14	167	no
15	179	no

Questions

What is x in 12x − 1 = 155?

The solution of 12x − 1 = 155 is x = 13.

How do you solve 12x − 1 = 155?

Add 1 to both sides to get 12x = 156, then divide both sides by 12 to get x = 13.

How do I check the answer?

Replace x by 13: 12(13) − 1 = 155, which is 155.

Solve 12x − 1 = 155

How to work it out

Trying values of x in 12x − 1 = 155

Questions

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