Solve 3x − 12 = 36

The solution of 3x − 12 = 36 is x = 16.

3x - 12 = 36\ \Rightarrow\ x = 16

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

The lines y = 3x − 12 and y = 36 meet at x = 16. 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.
$3x - 12 = 36$
2
Add 12 to both sides:
$3x - 12 + 12 = 36 + 12 \ \Rightarrow\ 3x = 48$
3
Divide both sides by 3:
$\frac{3x}{3} = \frac{48}{3} \ \Rightarrow\ x = 16$
4
Check: put x = 16 back into the equation.
$3\cdot16 - 12 = 48 - 12 = 36 \checkmark$

LaTeX source of the formulas on this page

\[ 3x - 12 = 36\ \Rightarrow\ x = 16 \]
\[ 3x - 12 = 36 \]
\[ 3x - 12 + 12 = 36 + 12 \ \Rightarrow\ 3x = 48 \]
\[ \frac{3x}{3} = \frac{48}{3} \ \Rightarrow\ x = 16 \]
\[ 3\cdot16 - 12 = 48 - 12 = 36 \checkmark \]

Trying values of x in 3x − 12 = 36

x	3x − 12	Equals 36?
14	30	no
15	33	no
16	36	yes
17	39	no
18	42	no

Questions

What is x in 3x − 12 = 36?

The solution of 3x − 12 = 36 is x = 16.

How do you solve 3x − 12 = 36?

Add 12 to both sides to get 3x = 48, then divide both sides by 3 to get x = 16.

How do I check the answer?

Replace x by 16: 3(16) − 12 = 36, which is 36.

Solve 3x − 12 = 36

How to work it out

Trying values of x in 3x − 12 = 36

Questions

Similar equations