Solve 4x − 12 = 20

The solution of 4x − 12 = 20 is x = 8.

4x - 12 = 20\ \Rightarrow\ x = 8

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

The lines y = 4x − 12 and y = 20 meet at x = 8. 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.
$4x - 12 = 20$
2
Add 12 to both sides:
$4x - 12 + 12 = 20 + 12 \ \Rightarrow\ 4x = 32$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{32}{4} \ \Rightarrow\ x = 8$
4
Check: put x = 8 back into the equation.
$4\cdot8 - 12 = 32 - 12 = 20 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 12 = 20\ \Rightarrow\ x = 8 \]
\[ 4x - 12 = 20 \]
\[ 4x - 12 + 12 = 20 + 12 \ \Rightarrow\ 4x = 32 \]
\[ \frac{4x}{4} = \frac{32}{4} \ \Rightarrow\ x = 8 \]
\[ 4\cdot8 - 12 = 32 - 12 = 20 \checkmark \]

Trying values of x in 4x − 12 = 20

x	4x − 12	Equals 20?
6	12	no
7	16	no
8	20	yes
9	24	no
10	28	no

Questions

What is x in 4x − 12 = 20?

The solution of 4x − 12 = 20 is x = 8.

How do you solve 4x − 12 = 20?

Add 12 to both sides to get 4x = 32, then divide both sides by 4 to get x = 8.

How do I check the answer?

Replace x by 8: 4(8) − 12 = 20, which is 20.

Solve 4x − 12 = 20

How to work it out

Trying values of x in 4x − 12 = 20

Questions

Similar equations