Solve 4x − 12 = 36

The solution of 4x − 12 = 36 is x = 12.

4x - 12 = 36\ \Rightarrow\ x = 12

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The lines y = 4x − 12 and y = 36 meet at x = 12. 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.
$4x - 12 = 36$
2
Add 12 to both sides:
$4x - 12 + 12 = 36 + 12 \ \Rightarrow\ 4x = 48$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{48}{4} \ \Rightarrow\ x = 12$
4
Check: put x = 12 back into the equation.
$4\cdot12 - 12 = 48 - 12 = 36 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 12 = 36\ \Rightarrow\ x = 12 \]
\[ 4x - 12 = 36 \]
\[ 4x - 12 + 12 = 36 + 12 \ \Rightarrow\ 4x = 48 \]
\[ \frac{4x}{4} = \frac{48}{4} \ \Rightarrow\ x = 12 \]
\[ 4\cdot12 - 12 = 48 - 12 = 36 \checkmark \]

Trying values of x in 4x − 12 = 36

x	4x − 12	Equals 36?
10	28	no
11	32	no
12	36	yes
13	40	no
14	44	no

Questions

What is x in 4x − 12 = 36?

The solution of 4x − 12 = 36 is x = 12.

How do you solve 4x − 12 = 36?

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

How do I check the answer?

Replace x by 12: 4(12) − 12 = 36, which is 36.

Solve 4x − 12 = 36

How to work it out

Trying values of x in 4x − 12 = 36

Questions

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