Solve 4x ā 1 = ā9
The solution of 4x ā 1 = ā9 is x = -2.
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 1 to both sides:
- 3
Divide both sides by 4:
- 4
Check: put x = -2 back into the equation.
LaTeX source of the formulas on this page
\[ 4x - 1 = -9\ \Rightarrow\ x = -2 \]
\[ 4x - 1 = -9 \]
\[ 4x - 1 + 1 = -9 + 1 \ \Rightarrow\ 4x = -8 \]
\[ \frac{4x}{4} = \frac{-8}{4} \ \Rightarrow\ x = -2 \]
\[ 4\cdot(-2) - 1 = -8 - 1 = -9 \checkmark \]Trying values of x in 4x ā 1 = ā9
| x | 4x ā 1 | Equals -9? |
|---|---|---|
| -4 | -17 | no |
| -3 | -13 | no |
| -2 | -9 | yes |
| -1 | -5 | no |
| 0 | -1 | no |
Questions
What is x in 4x ā 1 = ā9?
The solution of 4x ā 1 = ā9 is x = -2.
How do you solve 4x ā 1 = ā9?
Add 1 to both sides to get 4x = -8, then divide both sides by 4 to get x = -2.
How do I check the answer?
Replace x by -2: 4(-2) ā 1 = -9, which is -9.