Solve 10x − 10 = 90

The solution of 10x − 10 = 90 is x = 10.

10x - 10 = 90\ \Rightarrow\ x = 10

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The lines y = 10x − 10 and y = 90 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.
$10x - 10 = 90$
2
Add 10 to both sides:
$10x - 10 + 10 = 90 + 10 \ \Rightarrow\ 10x = 100$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{100}{10} \ \Rightarrow\ x = 10$
4
Check: put x = 10 back into the equation.
$10\cdot10 - 10 = 100 - 10 = 90 \checkmark$

LaTeX source of the formulas on this page

\[ 10x - 10 = 90\ \Rightarrow\ x = 10 \]
\[ 10x - 10 = 90 \]
\[ 10x - 10 + 10 = 90 + 10 \ \Rightarrow\ 10x = 100 \]
\[ \frac{10x}{10} = \frac{100}{10} \ \Rightarrow\ x = 10 \]
\[ 10\cdot10 - 10 = 100 - 10 = 90 \checkmark \]

Trying values of x in 10x − 10 = 90

x	10x − 10	Equals 90?
8	70	no
9	80	no
10	90	yes
11	100	no
12	110	no

Questions

What is x in 10x − 10 = 90?

The solution of 10x − 10 = 90 is x = 10.

How do you solve 10x − 10 = 90?

Add 10 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) − 10 = 90, which is 90.

Solve 10x − 10 = 90

How to work it out

Trying values of x in 10x − 10 = 90

Questions

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