Solve 9x − 15 = 111

The solution of 9x − 15 = 111 is x = 14.

9x - 15 = 111\ \Rightarrow\ x = 14

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

The lines y = 9x − 15 and y = 111 meet at x = 14. 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.
$9x - 15 = 111$
2
Add 15 to both sides:
$9x - 15 + 15 = 111 + 15 \ \Rightarrow\ 9x = 126$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{126}{9} \ \Rightarrow\ x = 14$
4
Check: put x = 14 back into the equation.
$9\cdot14 - 15 = 126 - 15 = 111 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 15 = 111\ \Rightarrow\ x = 14 \]
\[ 9x - 15 = 111 \]
\[ 9x - 15 + 15 = 111 + 15 \ \Rightarrow\ 9x = 126 \]
\[ \frac{9x}{9} = \frac{126}{9} \ \Rightarrow\ x = 14 \]
\[ 9\cdot14 - 15 = 126 - 15 = 111 \checkmark \]

Trying values of x in 9x − 15 = 111

x	9x − 15	Equals 111?
12	93	no
13	102	no
14	111	yes
15	120	no
16	129	no

Questions

What is x in 9x − 15 = 111?

The solution of 9x − 15 = 111 is x = 14.

How do you solve 9x − 15 = 111?

Add 15 to both sides to get 9x = 126, then divide both sides by 9 to get x = 14.

How do I check the answer?

Replace x by 14: 9(14) − 15 = 111, which is 111.

Solve 9x − 15 = 111

How to work it out

Trying values of x in 9x − 15 = 111

Questions

Similar equations