Solve 8x + 7 = 111
The solution of 8x + 7 = 111 is x = 13.
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 7 from both sides:
- 3
Divide both sides by 8:
- 4
Check: put x = 13 back into the equation.
LaTeX source of the formulas on this page
\[ 8x + 7 = 111\ \Rightarrow\ x = 13 \]
\[ 8x + 7 = 111 \]
\[ 8x + 7 - 7 = 111 - 7 \ \Rightarrow\ 8x = 104 \]
\[ \frac{8x}{8} = \frac{104}{8} \ \Rightarrow\ x = 13 \]
\[ 8\cdot13 + 7 = 104 + 7 = 111 \checkmark \]Trying values of x in 8x + 7 = 111
| x | 8x + 7 | Equals 111? |
|---|---|---|
| 11 | 95 | no |
| 12 | 103 | no |
| 13 | 111 | yes |
| 14 | 119 | no |
| 15 | 127 | no |
Questions
What is x in 8x + 7 = 111?
The solution of 8x + 7 = 111 is x = 13.
How do you solve 8x + 7 = 111?
Subtract 7 from both sides to get 8x = 104, then divide both sides by 8 to get x = 13.
How do I check the answer?
Replace x by 13: 8(13) + 7 = 111, which is 111.