Solve 7x + 6 = 90
The solution of 7x + 6 = 90 is x = 12.
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 6 from both sides:
- 3
Divide both sides by 7:
- 4
Check: put x = 12 back into the equation.
LaTeX source of the formulas on this page
\[ 7x + 6 = 90\ \Rightarrow\ x = 12 \]
\[ 7x + 6 = 90 \]
\[ 7x + 6 - 6 = 90 - 6 \ \Rightarrow\ 7x = 84 \]
\[ \frac{7x}{7} = \frac{84}{7} \ \Rightarrow\ x = 12 \]
\[ 7\cdot12 + 6 = 84 + 6 = 90 \checkmark \]Trying values of x in 7x + 6 = 90
| x | 7x + 6 | Equals 90? |
|---|---|---|
| 10 | 76 | no |
| 11 | 83 | no |
| 12 | 90 | yes |
| 13 | 97 | no |
| 14 | 104 | no |
Questions
What is x in 7x + 6 = 90?
The solution of 7x + 6 = 90 is x = 12.
How do you solve 7x + 6 = 90?
Subtract 6 from both sides to get 7x = 84, then divide both sides by 7 to get x = 12.
How do I check the answer?
Replace x by 12: 7(12) + 6 = 90, which is 90.