Solve 9x + 8 = −55

The solution of 9x + 8 = −55 is x = -7.

9x + 8 = -55\ \Rightarrow\ x = -7

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The lines y = 9x + 8 and y = -55 meet at x = -7. 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.
$9x + 8 = -55$
2
Subtract 8 from both sides:
$9x + 8 - 8 = -55 - 8 \ \Rightarrow\ 9x = -63$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{-63}{9} \ \Rightarrow\ x = -7$
4
Check: put x = -7 back into the equation.
$9\cdot(-7) + 8 = -63 + 8 = -55 \checkmark$

LaTeX source of the formulas on this page

\[ 9x + 8 = -55\ \Rightarrow\ x = -7 \]
\[ 9x + 8 = -55 \]
\[ 9x + 8 - 8 = -55 - 8 \ \Rightarrow\ 9x = -63 \]
\[ \frac{9x}{9} = \frac{-63}{9} \ \Rightarrow\ x = -7 \]
\[ 9\cdot(-7) + 8 = -63 + 8 = -55 \checkmark \]

Trying values of x in 9x + 8 = −55

x	9x + 8	Equals -55?
-9	-73	no
-8	-64	no
-7	-55	yes
-6	-46	no
-5	-37	no

Questions

What is x in 9x + 8 = −55?

The solution of 9x + 8 = −55 is x = -7.

How do you solve 9x + 8 = −55?

Subtract 8 from both sides to get 9x = -63, then divide both sides by 9 to get x = -7.

How do I check the answer?

Replace x by -7: 9(-7) + 8 = -55, which is -55.

Solve 9x + 8 = −55

How to work it out

Trying values of x in 9x + 8 = −55

Questions

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