Solve 8x − 8 = 128

The solution of 8x − 8 = 128 is x = 17.

8x - 8 = 128\ \Rightarrow\ x = 17

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

The lines y = 8x − 8 and y = 128 meet at x = 17. 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.
$8x - 8 = 128$
2
Add 8 to both sides:
$8x - 8 + 8 = 128 + 8 \ \Rightarrow\ 8x = 136$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{136}{8} \ \Rightarrow\ x = 17$
4
Check: put x = 17 back into the equation.
$8\cdot17 - 8 = 136 - 8 = 128 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 8 = 128\ \Rightarrow\ x = 17 \]
\[ 8x - 8 = 128 \]
\[ 8x - 8 + 8 = 128 + 8 \ \Rightarrow\ 8x = 136 \]
\[ \frac{8x}{8} = \frac{136}{8} \ \Rightarrow\ x = 17 \]
\[ 8\cdot17 - 8 = 136 - 8 = 128 \checkmark \]

Trying values of x in 8x − 8 = 128

x	8x − 8	Equals 128?
15	112	no
16	120	no
17	128	yes
18	136	no
19	144	no

Questions

What is x in 8x − 8 = 128?

The solution of 8x − 8 = 128 is x = 17.

How do you solve 8x − 8 = 128?

Add 8 to both sides to get 8x = 136, then divide both sides by 8 to get x = 17.

How do I check the answer?

Replace x by 17: 8(17) − 8 = 128, which is 128.

Solve 8x − 8 = 128

How to work it out

Trying values of x in 8x − 8 = 128

Questions

Similar equations