Solve 7x − 13 = 57

The solution of 7x − 13 = 57 is x = 10.

7x - 13 = 57\ \Rightarrow\ x = 10

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The lines y = 7x − 13 and y = 57 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.
$7x - 13 = 57$
2
Add 13 to both sides:
$7x - 13 + 13 = 57 + 13 \ \Rightarrow\ 7x = 70$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{70}{7} \ \Rightarrow\ x = 10$
4
Check: put x = 10 back into the equation.
$7\cdot10 - 13 = 70 - 13 = 57 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 13 = 57\ \Rightarrow\ x = 10 \]
\[ 7x - 13 = 57 \]
\[ 7x - 13 + 13 = 57 + 13 \ \Rightarrow\ 7x = 70 \]
\[ \frac{7x}{7} = \frac{70}{7} \ \Rightarrow\ x = 10 \]
\[ 7\cdot10 - 13 = 70 - 13 = 57 \checkmark \]

Trying values of x in 7x − 13 = 57

x	7x − 13	Equals 57?
8	43	no
9	50	no
10	57	yes
11	64	no
12	71	no

Questions

What is x in 7x − 13 = 57?

The solution of 7x − 13 = 57 is x = 10.

How do you solve 7x − 13 = 57?

Add 13 to both sides to get 7x = 70, then divide both sides by 7 to get x = 10.

How do I check the answer?

Replace x by 10: 7(10) − 13 = 57, which is 57.

Solve 7x − 13 = 57

How to work it out

Trying values of x in 7x − 13 = 57

Questions

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