Solve 2x + 9 = −1

The solution of 2x + 9 = −1 is x = -5.

2x + 9 = -1\ \Rightarrow\ x = -5

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The lines y = 2x + 9 and y = -1 meet at x = -5. 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.
$2x + 9 = -1$
2
Subtract 9 from both sides:
$2x + 9 - 9 = -1 - 9 \ \Rightarrow\ 2x = -10$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{-10}{2} \ \Rightarrow\ x = -5$
4
Check: put x = -5 back into the equation.
$2\cdot(-5) + 9 = -10 + 9 = -1 \checkmark$

LaTeX source of the formulas on this page

\[ 2x + 9 = -1\ \Rightarrow\ x = -5 \]
\[ 2x + 9 = -1 \]
\[ 2x + 9 - 9 = -1 - 9 \ \Rightarrow\ 2x = -10 \]
\[ \frac{2x}{2} = \frac{-10}{2} \ \Rightarrow\ x = -5 \]
\[ 2\cdot(-5) + 9 = -10 + 9 = -1 \checkmark \]

Trying values of x in 2x + 9 = −1

x	2x + 9	Equals -1?
-7	-5	no
-6	-3	no
-5	-1	yes
-4	1	no
-3	3	no

Questions

What is x in 2x + 9 = −1?

The solution of 2x + 9 = −1 is x = -5.

How do you solve 2x + 9 = −1?

Subtract 9 from both sides to get 2x = -10, then divide both sides by 2 to get x = -5.

How do I check the answer?

Replace x by -5: 2(-5) + 9 = -1, which is -1.

Solve 2x + 9 = −1

How to work it out

Trying values of x in 2x + 9 = −1

Questions

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