Solve 10x − 9 = −109

The solution of 10x − 9 = −109 is x = -10.

10x - 9 = -109\ \Rightarrow\ x = -10

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The lines y = 10x − 9 and y = -109 meet at x = -10. 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.
$10x - 9 = -109$
2
Add 9 to both sides:
$10x - 9 + 9 = -109 + 9 \ \Rightarrow\ 10x = -100$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{-100}{10} \ \Rightarrow\ x = -10$
4
Check: put x = -10 back into the equation.
$10\cdot(-10) - 9 = -100 - 9 = -109 \checkmark$

LaTeX source of the formulas on this page

\[ 10x - 9 = -109\ \Rightarrow\ x = -10 \]
\[ 10x - 9 = -109 \]
\[ 10x - 9 + 9 = -109 + 9 \ \Rightarrow\ 10x = -100 \]
\[ \frac{10x}{10} = \frac{-100}{10} \ \Rightarrow\ x = -10 \]
\[ 10\cdot(-10) - 9 = -100 - 9 = -109 \checkmark \]

Trying values of x in 10x − 9 = −109

x	10x − 9	Equals -109?
-12	-129	no
-11	-119	no
-10	-109	yes
-9	-99	no
-8	-89	no

Questions

What is x in 10x − 9 = −109?

The solution of 10x − 9 = −109 is x = -10.

How do you solve 10x − 9 = −109?

Add 9 to both sides to get 10x = -100, then divide both sides by 10 to get x = -10.

How do I check the answer?

Replace x by -10: 10(-10) − 9 = -109, which is -109.

Solve 10x − 9 = −109

How to work it out

Trying values of x in 10x − 9 = −109

Questions

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