Solve 4x + 9 = −23

The solution of 4x + 9 = −23 is x = -8.

4x + 9 = -23\ \Rightarrow\ x = -8

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The lines y = 4x + 9 and y = -23 meet at x = -8. 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 addition, then the multiplication.
$4x + 9 = -23$
2
Subtract 9 from both sides:
$4x + 9 - 9 = -23 - 9 \ \Rightarrow\ 4x = -32$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{-32}{4} \ \Rightarrow\ x = -8$
4
Check: put x = -8 back into the equation.
$4\cdot(-8) + 9 = -32 + 9 = -23 \checkmark$

LaTeX source of the formulas on this page

\[ 4x + 9 = -23\ \Rightarrow\ x = -8 \]
\[ 4x + 9 = -23 \]
\[ 4x + 9 - 9 = -23 - 9 \ \Rightarrow\ 4x = -32 \]
\[ \frac{4x}{4} = \frac{-32}{4} \ \Rightarrow\ x = -8 \]
\[ 4\cdot(-8) + 9 = -32 + 9 = -23 \checkmark \]

Trying values of x in 4x + 9 = −23

x	4x + 9	Equals -23?
-10	-31	no
-9	-27	no
-8	-23	yes
-7	-19	no
-6	-15	no

Questions

What is x in 4x + 9 = −23?

The solution of 4x + 9 = −23 is x = -8.

How do you solve 4x + 9 = −23?

Subtract 9 from both sides to get 4x = -32, then divide both sides by 4 to get x = -8.

How do I check the answer?

Replace x by -8: 4(-8) + 9 = -23, which is -23.

Solve 4x + 9 = −23

How to work it out

Trying values of x in 4x + 9 = −23

Questions

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