Solve 6x − 9 = 69

The solution of 6x − 9 = 69 is x = 13.

6x - 9 = 69\ \Rightarrow\ x = 13

Explain it step by step in chat Make a short video of it

The lines y = 6x − 9 and y = 69 meet at x = 13. 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.
$6x - 9 = 69$
2
Add 9 to both sides:
$6x - 9 + 9 = 69 + 9 \ \Rightarrow\ 6x = 78$
3
Divide both sides by 6:
$\frac{6x}{6} = \frac{78}{6} \ \Rightarrow\ x = 13$
4
Check: put x = 13 back into the equation.
$6\cdot13 - 9 = 78 - 9 = 69 \checkmark$

LaTeX source of the formulas on this page

\[ 6x - 9 = 69\ \Rightarrow\ x = 13 \]
\[ 6x - 9 = 69 \]
\[ 6x - 9 + 9 = 69 + 9 \ \Rightarrow\ 6x = 78 \]
\[ \frac{6x}{6} = \frac{78}{6} \ \Rightarrow\ x = 13 \]
\[ 6\cdot13 - 9 = 78 - 9 = 69 \checkmark \]

Trying values of x in 6x − 9 = 69

x	6x − 9	Equals 69?
11	57	no
12	63	no
13	69	yes
14	75	no
15	81	no

Questions

What is x in 6x − 9 = 69?

The solution of 6x − 9 = 69 is x = 13.

How do you solve 6x − 9 = 69?

Add 9 to both sides to get 6x = 78, then divide both sides by 6 to get x = 13.

How do I check the answer?

Replace x by 13: 6(13) − 9 = 69, which is 69.

Solve 6x − 9 = 69

How to work it out

Trying values of x in 6x − 9 = 69

Questions

Similar equations