Solve 7x − 13 = 85

The solution of 7x − 13 = 85 is x = 14.

7x - 13 = 85\ \Rightarrow\ x = 14

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The lines y = 7x − 13 and y = 85 meet at x = 14. 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.
$7x - 13 = 85$
2
Add 13 to both sides:
$7x - 13 + 13 = 85 + 13 \ \Rightarrow\ 7x = 98$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{98}{7} \ \Rightarrow\ x = 14$
4
Check: put x = 14 back into the equation.
$7\cdot14 - 13 = 98 - 13 = 85 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 13 = 85\ \Rightarrow\ x = 14 \]
\[ 7x - 13 = 85 \]
\[ 7x - 13 + 13 = 85 + 13 \ \Rightarrow\ 7x = 98 \]
\[ \frac{7x}{7} = \frac{98}{7} \ \Rightarrow\ x = 14 \]
\[ 7\cdot14 - 13 = 98 - 13 = 85 \checkmark \]

Trying values of x in 7x − 13 = 85

x	7x − 13	Equals 85?
12	71	no
13	78	no
14	85	yes
15	92	no
16	99	no

Questions

What is x in 7x − 13 = 85?

The solution of 7x − 13 = 85 is x = 14.

How do you solve 7x − 13 = 85?

Add 13 to both sides to get 7x = 98, then divide both sides by 7 to get x = 14.

How do I check the answer?

Replace x by 14: 7(14) − 13 = 85, which is 85.

Solve 7x − 13 = 85

How to work it out

Trying values of x in 7x − 13 = 85

Questions

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