Solve 9x − 1 = 89

The solution of 9x − 1 = 89 is x = 10.

9x - 1 = 89\ \Rightarrow\ x = 10

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

The lines y = 9x − 1 and y = 89 meet at x = 10. 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.
$9x - 1 = 89$
2
Add 1 to both sides:
$9x - 1 + 1 = 89 + 1 \ \Rightarrow\ 9x = 90$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{90}{9} \ \Rightarrow\ x = 10$
4
Check: put x = 10 back into the equation.
$9\cdot10 - 1 = 90 - 1 = 89 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 1 = 89\ \Rightarrow\ x = 10 \]
\[ 9x - 1 = 89 \]
\[ 9x - 1 + 1 = 89 + 1 \ \Rightarrow\ 9x = 90 \]
\[ \frac{9x}{9} = \frac{90}{9} \ \Rightarrow\ x = 10 \]
\[ 9\cdot10 - 1 = 90 - 1 = 89 \checkmark \]

Trying values of x in 9x − 1 = 89

x	9x − 1	Equals 89?
8	71	no
9	80	no
10	89	yes
11	98	no
12	107	no

Questions

What is x in 9x − 1 = 89?

The solution of 9x − 1 = 89 is x = 10.

How do you solve 9x − 1 = 89?

Add 1 to both sides to get 9x = 90, then divide both sides by 9 to get x = 10.

How do I check the answer?

Replace x by 10: 9(10) − 1 = 89, which is 89.

Solve 9x − 1 = 89

How to work it out

Trying values of x in 9x − 1 = 89

Questions

Similar equations