Solve 10x − 8 = 72

The solution of 10x − 8 = 72 is x = 8.

10x - 8 = 72\ \Rightarrow\ x = 8

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The lines y = 10x − 8 and y = 72 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.
$10x - 8 = 72$
2
Add 8 to both sides:
$10x - 8 + 8 = 72 + 8 \ \Rightarrow\ 10x = 80$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{80}{10} \ \Rightarrow\ x = 8$
4
Check: put x = 8 back into the equation.
$10\cdot8 - 8 = 80 - 8 = 72 \checkmark$

LaTeX source of the formulas on this page

\[ 10x - 8 = 72\ \Rightarrow\ x = 8 \]
\[ 10x - 8 = 72 \]
\[ 10x - 8 + 8 = 72 + 8 \ \Rightarrow\ 10x = 80 \]
\[ \frac{10x}{10} = \frac{80}{10} \ \Rightarrow\ x = 8 \]
\[ 10\cdot8 - 8 = 80 - 8 = 72 \checkmark \]

Trying values of x in 10x − 8 = 72

x	10x − 8	Equals 72?
6	52	no
7	62	no
8	72	yes
9	82	no
10	92	no

Questions

What is x in 10x − 8 = 72?

The solution of 10x − 8 = 72 is x = 8.

How do you solve 10x − 8 = 72?

Add 8 to both sides to get 10x = 80, then divide both sides by 10 to get x = 8.

How do I check the answer?

Replace x by 8: 10(8) − 8 = 72, which is 72.

Solve 10x − 8 = 72

How to work it out

Trying values of x in 10x − 8 = 72

Questions

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