Solve 4x − 12 = 24

The solution of 4x − 12 = 24 is x = 9.

4x - 12 = 24\ \Rightarrow\ x = 9

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The lines y = 4x − 12 and y = 24 meet at x = 9. 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.
$4x - 12 = 24$
2
Add 12 to both sides:
$4x - 12 + 12 = 24 + 12 \ \Rightarrow\ 4x = 36$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{36}{4} \ \Rightarrow\ x = 9$
4
Check: put x = 9 back into the equation.
$4\cdot9 - 12 = 36 - 12 = 24 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 12 = 24\ \Rightarrow\ x = 9 \]
\[ 4x - 12 = 24 \]
\[ 4x - 12 + 12 = 24 + 12 \ \Rightarrow\ 4x = 36 \]
\[ \frac{4x}{4} = \frac{36}{4} \ \Rightarrow\ x = 9 \]
\[ 4\cdot9 - 12 = 36 - 12 = 24 \checkmark \]

Trying values of x in 4x − 12 = 24

x	4x − 12	Equals 24?
7	16	no
8	20	no
9	24	yes
10	28	no
11	32	no

Questions

What is x in 4x − 12 = 24?

The solution of 4x − 12 = 24 is x = 9.

How do you solve 4x − 12 = 24?

Add 12 to both sides to get 4x = 36, then divide both sides by 4 to get x = 9.

How do I check the answer?

Replace x by 9: 4(9) − 12 = 24, which is 24.

Solve 4x − 12 = 24

How to work it out

Trying values of x in 4x − 12 = 24

Questions

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