Solve 2x + 7 = −9

The solution of 2x + 7 = −9 is x = -8.

2x + 7 = -9\ \Rightarrow\ x = -8

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The lines y = 2x + 7 and y = -9 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.
$2x + 7 = -9$
2
Subtract 7 from both sides:
$2x + 7 - 7 = -9 - 7 \ \Rightarrow\ 2x = -16$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{-16}{2} \ \Rightarrow\ x = -8$
4
Check: put x = -8 back into the equation.
$2\cdot(-8) + 7 = -16 + 7 = -9 \checkmark$

LaTeX source of the formulas on this page

\[ 2x + 7 = -9\ \Rightarrow\ x = -8 \]
\[ 2x + 7 = -9 \]
\[ 2x + 7 - 7 = -9 - 7 \ \Rightarrow\ 2x = -16 \]
\[ \frac{2x}{2} = \frac{-16}{2} \ \Rightarrow\ x = -8 \]
\[ 2\cdot(-8) + 7 = -16 + 7 = -9 \checkmark \]

Trying values of x in 2x + 7 = −9

x	2x + 7	Equals -9?
-10	-13	no
-9	-11	no
-8	-9	yes
-7	-7	no
-6	-5	no

Questions

What is x in 2x + 7 = −9?

The solution of 2x + 7 = −9 is x = -8.

How do you solve 2x + 7 = −9?

Subtract 7 from 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) + 7 = -9, which is -9.

Solve 2x + 7 = −9

How to work it out

Trying values of x in 2x + 7 = −9

Questions

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