Solve 7x − 13 = 8

The solution of 7x − 13 = 8 is x = 3.

7x - 13 = 8\ \Rightarrow\ x = 3

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The lines y = 7x − 13 and y = 8 meet at x = 3. 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.
$7x - 13 = 8$
2
Add 13 to both sides:
$7x - 13 + 13 = 8 + 13 \ \Rightarrow\ 7x = 21$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{21}{7} \ \Rightarrow\ x = 3$
4
Check: put x = 3 back into the equation.
$7\cdot3 - 13 = 21 - 13 = 8 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 13 = 8\ \Rightarrow\ x = 3 \]
\[ 7x - 13 = 8 \]
\[ 7x - 13 + 13 = 8 + 13 \ \Rightarrow\ 7x = 21 \]
\[ \frac{7x}{7} = \frac{21}{7} \ \Rightarrow\ x = 3 \]
\[ 7\cdot3 - 13 = 21 - 13 = 8 \checkmark \]

Trying values of x in 7x − 13 = 8

x	7x − 13	Equals 8?
1	-6	no
2	1	no
3	8	yes
4	15	no
5	22	no

Questions

What is x in 7x − 13 = 8?

The solution of 7x − 13 = 8 is x = 3.

How do you solve 7x − 13 = 8?

Add 13 to both sides to get 7x = 21, then divide both sides by 7 to get x = 3.

How do I check the answer?

Replace x by 3: 7(3) − 13 = 8, which is 8.

Solve 7x − 13 = 8

How to work it out

Trying values of x in 7x − 13 = 8

Questions

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