Solve 8x ā 5 = ā45
The solution of 8x ā 5 = ā45 is x = -5.
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.
- 2
Add 5 to both sides:
- 3
Divide both sides by 8:
- 4
Check: put x = -5 back into the equation.
LaTeX source of the formulas on this page
\[ 8x - 5 = -45\ \Rightarrow\ x = -5 \]
\[ 8x - 5 = -45 \]
\[ 8x - 5 + 5 = -45 + 5 \ \Rightarrow\ 8x = -40 \]
\[ \frac{8x}{8} = \frac{-40}{8} \ \Rightarrow\ x = -5 \]
\[ 8\cdot(-5) - 5 = -40 - 5 = -45 \checkmark \]Trying values of x in 8x ā 5 = ā45
| x | 8x ā 5 | Equals -45? |
|---|---|---|
| -7 | -61 | no |
| -6 | -53 | no |
| -5 | -45 | yes |
| -4 | -37 | no |
| -3 | -29 | no |
Questions
What is x in 8x ā 5 = ā45?
The solution of 8x ā 5 = ā45 is x = -5.
How do you solve 8x ā 5 = ā45?
Add 5 to both sides to get 8x = -40, then divide both sides by 8 to get x = -5.
How do I check the answer?
Replace x by -5: 8(-5) ā 5 = -45, which is -45.