Solve 4x − 15 = −23

The solution of 4x − 15 = −23 is x = -2.

4x - 15 = -23\ \Rightarrow\ x = -2

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The lines y = 4x − 15 and y = -23 meet at x = -2. 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.
$4x - 15 = -23$
2
Add 15 to both sides:
$4x - 15 + 15 = -23 + 15 \ \Rightarrow\ 4x = -8$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{-8}{4} \ \Rightarrow\ x = -2$
4
Check: put x = -2 back into the equation.
$4\cdot(-2) - 15 = -8 - 15 = -23 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 15 = -23\ \Rightarrow\ x = -2 \]
\[ 4x - 15 = -23 \]
\[ 4x - 15 + 15 = -23 + 15 \ \Rightarrow\ 4x = -8 \]
\[ \frac{4x}{4} = \frac{-8}{4} \ \Rightarrow\ x = -2 \]
\[ 4\cdot(-2) - 15 = -8 - 15 = -23 \checkmark \]

Trying values of x in 4x − 15 = −23

x	4x − 15	Equals -23?
-4	-31	no
-3	-27	no
-2	-23	yes
-1	-19	no
0	-15	no

Questions

What is x in 4x − 15 = −23?

The solution of 4x − 15 = −23 is x = -2.

How do you solve 4x − 15 = −23?

Add 15 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) − 15 = -23, which is -23.

Solve 4x − 15 = −23

How to work it out

Trying values of x in 4x − 15 = −23

Questions

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