Solve 8x − 7 = 89

The solution of 8x − 7 = 89 is x = 12.

8x - 7 = 89\ \Rightarrow\ x = 12

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The lines y = 8x − 7 and y = 89 meet at x = 12. 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.
$8x - 7 = 89$
2
Add 7 to both sides:
$8x - 7 + 7 = 89 + 7 \ \Rightarrow\ 8x = 96$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{96}{8} \ \Rightarrow\ x = 12$
4
Check: put x = 12 back into the equation.
$8\cdot12 - 7 = 96 - 7 = 89 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 7 = 89\ \Rightarrow\ x = 12 \]
\[ 8x - 7 = 89 \]
\[ 8x - 7 + 7 = 89 + 7 \ \Rightarrow\ 8x = 96 \]
\[ \frac{8x}{8} = \frac{96}{8} \ \Rightarrow\ x = 12 \]
\[ 8\cdot12 - 7 = 96 - 7 = 89 \checkmark \]

Trying values of x in 8x − 7 = 89

x	8x − 7	Equals 89?
10	73	no
11	81	no
12	89	yes
13	97	no
14	105	no

Questions

What is x in 8x − 7 = 89?

The solution of 8x − 7 = 89 is x = 12.

How do you solve 8x − 7 = 89?

Add 7 to both sides to get 8x = 96, then divide both sides by 8 to get x = 12.

How do I check the answer?

Replace x by 12: 8(12) − 7 = 89, which is 89.

Solve 8x − 7 = 89

How to work it out

Trying values of x in 8x − 7 = 89

Questions

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