Solve 9x − 8 = −89

The solution of 9x − 8 = −89 is x = -9.

9x - 8 = -89\ \Rightarrow\ x = -9

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The lines y = 9x − 8 and y = -89 meet at x = -9. 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.
$9x - 8 = -89$
2
Add 8 to both sides:
$9x - 8 + 8 = -89 + 8 \ \Rightarrow\ 9x = -81$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{-81}{9} \ \Rightarrow\ x = -9$
4
Check: put x = -9 back into the equation.
$9\cdot(-9) - 8 = -81 - 8 = -89 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 8 = -89\ \Rightarrow\ x = -9 \]
\[ 9x - 8 = -89 \]
\[ 9x - 8 + 8 = -89 + 8 \ \Rightarrow\ 9x = -81 \]
\[ \frac{9x}{9} = \frac{-81}{9} \ \Rightarrow\ x = -9 \]
\[ 9\cdot(-9) - 8 = -81 - 8 = -89 \checkmark \]

Trying values of x in 9x − 8 = −89

x	9x − 8	Equals -89?
-11	-107	no
-10	-98	no
-9	-89	yes
-8	-80	no
-7	-71	no

Questions

What is x in 9x − 8 = −89?

The solution of 9x − 8 = −89 is x = -9.

How do you solve 9x − 8 = −89?

Add 8 to both sides to get 9x = -81, then divide both sides by 9 to get x = -9.

How do I check the answer?

Replace x by -9: 9(-9) − 8 = -89, which is -89.

Solve 9x − 8 = −89

How to work it out

Trying values of x in 9x − 8 = −89

Questions

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