Solve 8x − 15 = 89

The solution of 8x − 15 = 89 is x = 13.

8x - 15 = 89\ \Rightarrow\ x = 13

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

The lines y = 8x − 15 and y = 89 meet at x = 13. 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.
$8x - 15 = 89$
2
Add 15 to both sides:
$8x - 15 + 15 = 89 + 15 \ \Rightarrow\ 8x = 104$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{104}{8} \ \Rightarrow\ x = 13$
4
Check: put x = 13 back into the equation.
$8\cdot13 - 15 = 104 - 15 = 89 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 15 = 89\ \Rightarrow\ x = 13 \]
\[ 8x - 15 = 89 \]
\[ 8x - 15 + 15 = 89 + 15 \ \Rightarrow\ 8x = 104 \]
\[ \frac{8x}{8} = \frac{104}{8} \ \Rightarrow\ x = 13 \]
\[ 8\cdot13 - 15 = 104 - 15 = 89 \checkmark \]

Trying values of x in 8x − 15 = 89

x	8x − 15	Equals 89?
11	73	no
12	81	no
13	89	yes
14	97	no
15	105	no

Questions

What is x in 8x − 15 = 89?

The solution of 8x − 15 = 89 is x = 13.

How do you solve 8x − 15 = 89?

Add 15 to both sides to get 8x = 104, then divide both sides by 8 to get x = 13.

How do I check the answer?

Replace x by 13: 8(13) − 15 = 89, which is 89.

Solve 8x − 15 = 89

How to work it out

Trying values of x in 8x − 15 = 89

Questions

Similar equations