Solve 11x − 9 = 79

The solution of 11x − 9 = 79 is x = 8.

11x - 9 = 79\ \Rightarrow\ x = 8

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The lines y = 11x − 9 and y = 79 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.
$11x - 9 = 79$
2
Add 9 to both sides:
$11x - 9 + 9 = 79 + 9 \ \Rightarrow\ 11x = 88$
3
Divide both sides by 11:
$\frac{11x}{11} = \frac{88}{11} \ \Rightarrow\ x = 8$
4
Check: put x = 8 back into the equation.
$11\cdot8 - 9 = 88 - 9 = 79 \checkmark$

LaTeX source of the formulas on this page

\[ 11x - 9 = 79\ \Rightarrow\ x = 8 \]
\[ 11x - 9 = 79 \]
\[ 11x - 9 + 9 = 79 + 9 \ \Rightarrow\ 11x = 88 \]
\[ \frac{11x}{11} = \frac{88}{11} \ \Rightarrow\ x = 8 \]
\[ 11\cdot8 - 9 = 88 - 9 = 79 \checkmark \]

Trying values of x in 11x − 9 = 79

x	11x − 9	Equals 79?
6	57	no
7	68	no
8	79	yes
9	90	no
10	101	no

Questions

What is x in 11x − 9 = 79?

The solution of 11x − 9 = 79 is x = 8.

How do you solve 11x − 9 = 79?

Add 9 to both sides to get 11x = 88, then divide both sides by 11 to get x = 8.

How do I check the answer?

Replace x by 8: 11(8) − 9 = 79, which is 79.

Solve 11x − 9 = 79

How to work it out

Trying values of x in 11x − 9 = 79

Questions

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