Solve 2x − 9 = −15

The solution of 2x − 9 = −15 is x = -3.

2x - 9 = -15\ \Rightarrow\ x = -3

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The lines y = 2x − 9 and y = -15 meet at x = -3. 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.
$2x - 9 = -15$
2
Add 9 to both sides:
$2x - 9 + 9 = -15 + 9 \ \Rightarrow\ 2x = -6$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{-6}{2} \ \Rightarrow\ x = -3$
4
Check: put x = -3 back into the equation.
$2\cdot(-3) - 9 = -6 - 9 = -15 \checkmark$

LaTeX source of the formulas on this page

\[ 2x - 9 = -15\ \Rightarrow\ x = -3 \]
\[ 2x - 9 = -15 \]
\[ 2x - 9 + 9 = -15 + 9 \ \Rightarrow\ 2x = -6 \]
\[ \frac{2x}{2} = \frac{-6}{2} \ \Rightarrow\ x = -3 \]
\[ 2\cdot(-3) - 9 = -6 - 9 = -15 \checkmark \]

Trying values of x in 2x − 9 = −15

x	2x − 9	Equals -15?
-5	-19	no
-4	-17	no
-3	-15	yes
-2	-13	no
-1	-11	no

Questions

What is x in 2x − 9 = −15?

The solution of 2x − 9 = −15 is x = -3.

How do you solve 2x − 9 = −15?

Add 9 to both sides to get 2x = -6, then divide both sides by 2 to get x = -3.

How do I check the answer?

Replace x by -3: 2(-3) − 9 = -15, which is -15.

Solve 2x − 9 = −15

How to work it out

Trying values of x in 2x − 9 = −15

Questions

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