Solve 6x − 9 = 111

The solution of 6x − 9 = 111 is x = 20.

6x - 9 = 111\ \Rightarrow\ x = 20

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The lines y = 6x − 9 and y = 111 meet at x = 20. 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.
$6x - 9 = 111$
2
Add 9 to both sides:
$6x - 9 + 9 = 111 + 9 \ \Rightarrow\ 6x = 120$
3
Divide both sides by 6:
$\frac{6x}{6} = \frac{120}{6} \ \Rightarrow\ x = 20$
4
Check: put x = 20 back into the equation.
$6\cdot20 - 9 = 120 - 9 = 111 \checkmark$

LaTeX source of the formulas on this page

\[ 6x - 9 = 111\ \Rightarrow\ x = 20 \]
\[ 6x - 9 = 111 \]
\[ 6x - 9 + 9 = 111 + 9 \ \Rightarrow\ 6x = 120 \]
\[ \frac{6x}{6} = \frac{120}{6} \ \Rightarrow\ x = 20 \]
\[ 6\cdot20 - 9 = 120 - 9 = 111 \checkmark \]

Trying values of x in 6x − 9 = 111

x	6x − 9	Equals 111?
18	99	no
19	105	no
20	111	yes
21	117	no
22	123	no

Questions

What is x in 6x − 9 = 111?

The solution of 6x − 9 = 111 is x = 20.

How do you solve 6x − 9 = 111?

Add 9 to both sides to get 6x = 120, then divide both sides by 6 to get x = 20.

How do I check the answer?

Replace x by 20: 6(20) − 9 = 111, which is 111.

Solve 6x − 9 = 111

How to work it out

Trying values of x in 6x − 9 = 111

Questions

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