Solve 7x + 13 = 20
The solution of 7x + 13 = 20 is x = 1.
How to work it out
- 1
The goal is to get x alone. Undo the operations in the opposite order: first the addition, then the multiplication.
- 2
Subtract 13 from both sides:
- 3
Divide both sides by 7:
- 4
Check: put x = 1 back into the equation.
LaTeX source of the formulas on this page
\[ 7x + 13 = 20\ \Rightarrow\ x = 1 \]
\[ 7x + 13 = 20 \]
\[ 7x + 13 - 13 = 20 - 13 \ \Rightarrow\ 7x = 7 \]
\[ \frac{7x}{7} = \frac{7}{7} \ \Rightarrow\ x = 1 \]
\[ 7\cdot1 + 13 = 7 + 13 = 20 \checkmark \]Trying values of x in 7x + 13 = 20
| x | 7x + 13 | Equals 20? |
|---|---|---|
| -1 | 6 | no |
| 0 | 13 | no |
| 1 | 20 | yes |
| 2 | 27 | no |
| 3 | 34 | no |
Questions
What is x in 7x + 13 = 20?
The solution of 7x + 13 = 20 is x = 1.
How do you solve 7x + 13 = 20?
Subtract 13 from both sides to get 7x = 7, then divide both sides by 7 to get x = 1.
How do I check the answer?
Replace x by 1: 7(1) + 13 = 20, which is 20.