Solve 10x + 4 = 84
The solution of 10x + 4 = 84 is x = 8.
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 4 from both sides:
- 3
Divide both sides by 10:
- 4
Check: put x = 8 back into the equation.
LaTeX source of the formulas on this page
\[ 10x + 4 = 84\ \Rightarrow\ x = 8 \]
\[ 10x + 4 = 84 \]
\[ 10x + 4 - 4 = 84 - 4 \ \Rightarrow\ 10x = 80 \]
\[ \frac{10x}{10} = \frac{80}{10} \ \Rightarrow\ x = 8 \]
\[ 10\cdot8 + 4 = 80 + 4 = 84 \checkmark \]Trying values of x in 10x + 4 = 84
| x | 10x + 4 | Equals 84? |
|---|---|---|
| 6 | 64 | no |
| 7 | 74 | no |
| 8 | 84 | yes |
| 9 | 94 | no |
| 10 | 104 | no |
Questions
What is x in 10x + 4 = 84?
The solution of 10x + 4 = 84 is x = 8.
How do you solve 10x + 4 = 84?
Subtract 4 from both sides to get 10x = 80, then divide both sides by 10 to get x = 8.
How do I check the answer?
Replace x by 8: 10(8) + 4 = 84, which is 84.