Solve 9x − 11 = 70

The solution of 9x − 11 = 70 is x = 9.

9x - 11 = 70\ \Rightarrow\ x = 9

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The lines y = 9x − 11 and y = 70 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.
$9x - 11 = 70$
2
Add 11 to both sides:
$9x - 11 + 11 = 70 + 11 \ \Rightarrow\ 9x = 81$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{81}{9} \ \Rightarrow\ x = 9$
4
Check: put x = 9 back into the equation.
$9\cdot9 - 11 = 81 - 11 = 70 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 11 = 70\ \Rightarrow\ x = 9 \]
\[ 9x - 11 = 70 \]
\[ 9x - 11 + 11 = 70 + 11 \ \Rightarrow\ 9x = 81 \]
\[ \frac{9x}{9} = \frac{81}{9} \ \Rightarrow\ x = 9 \]
\[ 9\cdot9 - 11 = 81 - 11 = 70 \checkmark \]

Trying values of x in 9x − 11 = 70

x	9x − 11	Equals 70?
7	52	no
8	61	no
9	70	yes
10	79	no
11	88	no

Questions

What is x in 9x − 11 = 70?

The solution of 9x − 11 = 70 is x = 9.

How do you solve 9x − 11 = 70?

Add 11 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) − 11 = 70, which is 70.

Solve 9x − 11 = 70

How to work it out

Trying values of x in 9x − 11 = 70

Questions

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