Solve 10x − 1 = −91

The solution of 10x − 1 = −91 is x = -9.

10x - 1 = -91\ \Rightarrow\ x = -9

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The lines y = 10x − 1 and y = -91 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.
$10x - 1 = -91$
2
Add 1 to both sides:
$10x - 1 + 1 = -91 + 1 \ \Rightarrow\ 10x = -90$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{-90}{10} \ \Rightarrow\ x = -9$
4
Check: put x = -9 back into the equation.
$10\cdot(-9) - 1 = -90 - 1 = -91 \checkmark$

LaTeX source of the formulas on this page

\[ 10x - 1 = -91\ \Rightarrow\ x = -9 \]
\[ 10x - 1 = -91 \]
\[ 10x - 1 + 1 = -91 + 1 \ \Rightarrow\ 10x = -90 \]
\[ \frac{10x}{10} = \frac{-90}{10} \ \Rightarrow\ x = -9 \]
\[ 10\cdot(-9) - 1 = -90 - 1 = -91 \checkmark \]

Trying values of x in 10x − 1 = −91

x	10x − 1	Equals -91?
-11	-111	no
-10	-101	no
-9	-91	yes
-8	-81	no
-7	-71	no

Questions

What is x in 10x − 1 = −91?

The solution of 10x − 1 = −91 is x = -9.

How do you solve 10x − 1 = −91?

Add 1 to both sides to get 10x = -90, then divide both sides by 10 to get x = -9.

How do I check the answer?

Replace x by -9: 10(-9) − 1 = -91, which is -91.

Solve 10x − 1 = −91

How to work it out

Trying values of x in 10x − 1 = −91

Questions

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