Solve 10x − 9 = −89

The solution of 10x − 9 = −89 is x = -8.

10x - 9 = -89\ \Rightarrow\ x = -8

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The lines y = 10x − 9 and y = -89 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 subtraction, then the multiplication.
$10x - 9 = -89$
2
Add 9 to both sides:
$10x - 9 + 9 = -89 + 9 \ \Rightarrow\ 10x = -80$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{-80}{10} \ \Rightarrow\ x = -8$
4
Check: put x = -8 back into the equation.
$10\cdot(-8) - 9 = -80 - 9 = -89 \checkmark$

LaTeX source of the formulas on this page

\[ 10x - 9 = -89\ \Rightarrow\ x = -8 \]
\[ 10x - 9 = -89 \]
\[ 10x - 9 + 9 = -89 + 9 \ \Rightarrow\ 10x = -80 \]
\[ \frac{10x}{10} = \frac{-80}{10} \ \Rightarrow\ x = -8 \]
\[ 10\cdot(-8) - 9 = -80 - 9 = -89 \checkmark \]

Trying values of x in 10x − 9 = −89

x	10x − 9	Equals -89?
-10	-109	no
-9	-99	no
-8	-89	yes
-7	-79	no
-6	-69	no

Questions

What is x in 10x − 9 = −89?

The solution of 10x − 9 = −89 is x = -8.

How do you solve 10x − 9 = −89?

Add 9 to both sides to get 10x = -80, then divide both sides by 10 to get x = -8.

How do I check the answer?

Replace x by -8: 10(-8) − 9 = -89, which is -89.

Solve 10x − 9 = −89

How to work it out

Trying values of x in 10x − 9 = −89

Questions

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