Solve 9x + 8 = −1

The solution of 9x + 8 = −1 is x = -1.

9x + 8 = -1\ \Rightarrow\ x = -1

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The lines y = 9x + 8 and y = -1 meet at x = -1. 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.
$9x + 8 = -1$
2
Subtract 8 from both sides:
$9x + 8 - 8 = -1 - 8 \ \Rightarrow\ 9x = -9$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{-9}{9} \ \Rightarrow\ x = -1$
4
Check: put x = -1 back into the equation.
$9\cdot(-1) + 8 = -9 + 8 = -1 \checkmark$

LaTeX source of the formulas on this page

\[ 9x + 8 = -1\ \Rightarrow\ x = -1 \]
\[ 9x + 8 = -1 \]
\[ 9x + 8 - 8 = -1 - 8 \ \Rightarrow\ 9x = -9 \]
\[ \frac{9x}{9} = \frac{-9}{9} \ \Rightarrow\ x = -1 \]
\[ 9\cdot(-1) + 8 = -9 + 8 = -1 \checkmark \]

Trying values of x in 9x + 8 = −1

x	9x + 8	Equals -1?
-3	-19	no
-2	-10	no
-1	-1	yes
0	8	no
1	17	no

Questions

What is x in 9x + 8 = −1?

The solution of 9x + 8 = −1 is x = -1.

How do you solve 9x + 8 = −1?

Subtract 8 from both sides to get 9x = -9, then divide both sides by 9 to get x = -1.

How do I check the answer?

Replace x by -1: 9(-1) + 8 = -1, which is -1.

Solve 9x + 8 = −1

How to work it out

Trying values of x in 9x + 8 = −1

Questions

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