Solve 9x − 8 = 82

The solution of 9x − 8 = 82 is x = 10.

9x - 8 = 82\ \Rightarrow\ x = 10

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The lines y = 9x − 8 and y = 82 meet at x = 10. 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.
$9x - 8 = 82$
2
Add 8 to both sides:
$9x - 8 + 8 = 82 + 8 \ \Rightarrow\ 9x = 90$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{90}{9} \ \Rightarrow\ x = 10$
4
Check: put x = 10 back into the equation.
$9\cdot10 - 8 = 90 - 8 = 82 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 8 = 82\ \Rightarrow\ x = 10 \]
\[ 9x - 8 = 82 \]
\[ 9x - 8 + 8 = 82 + 8 \ \Rightarrow\ 9x = 90 \]
\[ \frac{9x}{9} = \frac{90}{9} \ \Rightarrow\ x = 10 \]
\[ 9\cdot10 - 8 = 90 - 8 = 82 \checkmark \]

Trying values of x in 9x − 8 = 82

x	9x − 8	Equals 82?
8	64	no
9	73	no
10	82	yes
11	91	no
12	100	no

Questions

What is x in 9x − 8 = 82?

The solution of 9x − 8 = 82 is x = 10.

How do you solve 9x − 8 = 82?

Add 8 to both sides to get 9x = 90, then divide both sides by 9 to get x = 10.

How do I check the answer?

Replace x by 10: 9(10) − 8 = 82, which is 82.

Solve 9x − 8 = 82

How to work it out

Trying values of x in 9x − 8 = 82

Questions

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