Solve 4x − 9 = −13

The solution of 4x − 9 = −13 is x = -1.

4x - 9 = -13\ \Rightarrow\ x = -1

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The lines y = 4x − 9 and y = -13 meet at x = -1. The solution of the equation is the x-coordinate of the point where the two sides are equal.

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.
$4x - 9 = -13$
2
Add 9 to both sides:
$4x - 9 + 9 = -13 + 9 \ \Rightarrow\ 4x = -4$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{-4}{4} \ \Rightarrow\ x = -1$
4
Check: put x = -1 back into the equation.
$4\cdot(-1) - 9 = -4 - 9 = -13 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 9 = -13\ \Rightarrow\ x = -1 \]
\[ 4x - 9 = -13 \]
\[ 4x - 9 + 9 = -13 + 9 \ \Rightarrow\ 4x = -4 \]
\[ \frac{4x}{4} = \frac{-4}{4} \ \Rightarrow\ x = -1 \]
\[ 4\cdot(-1) - 9 = -4 - 9 = -13 \checkmark \]

Trying values of x in 4x − 9 = −13

x	4x − 9	Equals -13?
-3	-21	no
-2	-17	no
-1	-13	yes
0	-9	no
1	-5	no

Questions

What is x in 4x − 9 = −13?

The solution of 4x − 9 = −13 is x = -1.

How do you solve 4x − 9 = −13?

Add 9 to both sides to get 4x = -4, then divide both sides by 4 to get x = -1.

How do I check the answer?

Replace x by -1: 4(-1) − 9 = -13, which is -13.

Solve 4x − 9 = −13

How to work it out

Trying values of x in 4x − 9 = −13

Questions

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