Solve 7x − 9 = 82

The solution of 7x − 9 = 82 is x = 13.

7x - 9 = 82\ \Rightarrow\ x = 13

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

The lines y = 7x − 9 and y = 82 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.
$7x - 9 = 82$
2
Add 9 to both sides:
$7x - 9 + 9 = 82 + 9 \ \Rightarrow\ 7x = 91$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{91}{7} \ \Rightarrow\ x = 13$
4
Check: put x = 13 back into the equation.
$7\cdot13 - 9 = 91 - 9 = 82 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 9 = 82\ \Rightarrow\ x = 13 \]
\[ 7x - 9 = 82 \]
\[ 7x - 9 + 9 = 82 + 9 \ \Rightarrow\ 7x = 91 \]
\[ \frac{7x}{7} = \frac{91}{7} \ \Rightarrow\ x = 13 \]
\[ 7\cdot13 - 9 = 91 - 9 = 82 \checkmark \]

Trying values of x in 7x − 9 = 82

x	7x − 9	Equals 82?
11	68	no
12	75	no
13	82	yes
14	89	no
15	96	no

Questions

What is x in 7x − 9 = 82?

The solution of 7x − 9 = 82 is x = 13.

How do you solve 7x − 9 = 82?

Add 9 to both sides to get 7x = 91, then divide both sides by 7 to get x = 13.

How do I check the answer?

Replace x by 13: 7(13) − 9 = 82, which is 82.

Solve 7x − 9 = 82

How to work it out

Trying values of x in 7x − 9 = 82

Questions

Similar equations