Solve 2x − 15 = −31

The solution of 2x − 15 = −31 is x = -8.

2x - 15 = -31\ \Rightarrow\ x = -8

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The lines y = 2x − 15 and y = -31 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 subtraction, then the multiplication.
$2x - 15 = -31$
2
Add 15 to both sides:
$2x - 15 + 15 = -31 + 15 \ \Rightarrow\ 2x = -16$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{-16}{2} \ \Rightarrow\ x = -8$
4
Check: put x = -8 back into the equation.
$2\cdot(-8) - 15 = -16 - 15 = -31 \checkmark$

LaTeX source of the formulas on this page

\[ 2x - 15 = -31\ \Rightarrow\ x = -8 \]
\[ 2x - 15 = -31 \]
\[ 2x - 15 + 15 = -31 + 15 \ \Rightarrow\ 2x = -16 \]
\[ \frac{2x}{2} = \frac{-16}{2} \ \Rightarrow\ x = -8 \]
\[ 2\cdot(-8) - 15 = -16 - 15 = -31 \checkmark \]

Trying values of x in 2x − 15 = −31

x	2x − 15	Equals -31?
-10	-35	no
-9	-33	no
-8	-31	yes
-7	-29	no
-6	-27	no

Questions

What is x in 2x − 15 = −31?

The solution of 2x − 15 = −31 is x = -8.

How do you solve 2x − 15 = −31?

Add 15 to both sides to get 2x = -16, then divide both sides by 2 to get x = -8.

How do I check the answer?

Replace x by -8: 2(-8) − 15 = -31, which is -31.

Solve 2x − 15 = −31

How to work it out

Trying values of x in 2x − 15 = −31

Questions

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