Solve 8x − 11 = 109

The solution of 8x − 11 = 109 is x = 15.

8x - 11 = 109\ \Rightarrow\ x = 15

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The lines y = 8x − 11 and y = 109 meet at x = 15. 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.
$8x - 11 = 109$
2
Add 11 to both sides:
$8x - 11 + 11 = 109 + 11 \ \Rightarrow\ 8x = 120$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{120}{8} \ \Rightarrow\ x = 15$
4
Check: put x = 15 back into the equation.
$8\cdot15 - 11 = 120 - 11 = 109 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 11 = 109\ \Rightarrow\ x = 15 \]
\[ 8x - 11 = 109 \]
\[ 8x - 11 + 11 = 109 + 11 \ \Rightarrow\ 8x = 120 \]
\[ \frac{8x}{8} = \frac{120}{8} \ \Rightarrow\ x = 15 \]
\[ 8\cdot15 - 11 = 120 - 11 = 109 \checkmark \]

Trying values of x in 8x − 11 = 109

x	8x − 11	Equals 109?
13	93	no
14	101	no
15	109	yes
16	117	no
17	125	no

Questions

What is x in 8x − 11 = 109?

The solution of 8x − 11 = 109 is x = 15.

How do you solve 8x − 11 = 109?

Add 11 to both sides to get 8x = 120, then divide both sides by 8 to get x = 15.

How do I check the answer?

Replace x by 15: 8(15) − 11 = 109, which is 109.

Solve 8x − 11 = 109

How to work it out

Trying values of x in 8x − 11 = 109

Questions

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