Solve 5x − 12 = 28

The solution of 5x − 12 = 28 is x = 8.

5x - 12 = 28\ \Rightarrow\ x = 8

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The lines y = 5x − 12 and y = 28 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.
$5x - 12 = 28$
2
Add 12 to both sides:
$5x - 12 + 12 = 28 + 12 \ \Rightarrow\ 5x = 40$
3
Divide both sides by 5:
$\frac{5x}{5} = \frac{40}{5} \ \Rightarrow\ x = 8$
4
Check: put x = 8 back into the equation.
$5\cdot8 - 12 = 40 - 12 = 28 \checkmark$

LaTeX source of the formulas on this page

\[ 5x - 12 = 28\ \Rightarrow\ x = 8 \]
\[ 5x - 12 = 28 \]
\[ 5x - 12 + 12 = 28 + 12 \ \Rightarrow\ 5x = 40 \]
\[ \frac{5x}{5} = \frac{40}{5} \ \Rightarrow\ x = 8 \]
\[ 5\cdot8 - 12 = 40 - 12 = 28 \checkmark \]

Trying values of x in 5x − 12 = 28

x	5x − 12	Equals 28?
6	18	no
7	23	no
8	28	yes
9	33	no
10	38	no

Questions

What is x in 5x − 12 = 28?

The solution of 5x − 12 = 28 is x = 8.

How do you solve 5x − 12 = 28?

Add 12 to both sides to get 5x = 40, then divide both sides by 5 to get x = 8.

How do I check the answer?

Replace x by 8: 5(8) − 12 = 28, which is 28.

Solve 5x − 12 = 28

How to work it out

Trying values of x in 5x − 12 = 28

Questions

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