Solve 9x − 10 = 80

The solution of 9x − 10 = 80 is x = 10.

9x - 10 = 80\ \Rightarrow\ x = 10

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

The lines y = 9x − 10 and y = 80 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.
$9x - 10 = 80$
2
Add 10 to both sides:
$9x - 10 + 10 = 80 + 10 \ \Rightarrow\ 9x = 90$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{90}{9} \ \Rightarrow\ x = 10$
4
Check: put x = 10 back into the equation.
$9\cdot10 - 10 = 90 - 10 = 80 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 10 = 80\ \Rightarrow\ x = 10 \]
\[ 9x - 10 = 80 \]
\[ 9x - 10 + 10 = 80 + 10 \ \Rightarrow\ 9x = 90 \]
\[ \frac{9x}{9} = \frac{90}{9} \ \Rightarrow\ x = 10 \]
\[ 9\cdot10 - 10 = 90 - 10 = 80 \checkmark \]

Trying values of x in 9x − 10 = 80

x	9x − 10	Equals 80?
8	62	no
9	71	no
10	80	yes
11	89	no
12	98	no

Questions

What is x in 9x − 10 = 80?

The solution of 9x − 10 = 80 is x = 10.

How do you solve 9x − 10 = 80?

Add 10 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) − 10 = 80, which is 80.

Solve 9x − 10 = 80

How to work it out

Trying values of x in 9x − 10 = 80

Questions

Similar equations