Solve 5x − 5 = 80

The solution of 5x − 5 = 80 is x = 17.

5x - 5 = 80\ \Rightarrow\ x = 17

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

The lines y = 5x − 5 and y = 80 meet at x = 17. 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.
$5x - 5 = 80$
2
Add 5 to both sides:
$5x - 5 + 5 = 80 + 5 \ \Rightarrow\ 5x = 85$
3
Divide both sides by 5:
$\frac{5x}{5} = \frac{85}{5} \ \Rightarrow\ x = 17$
4
Check: put x = 17 back into the equation.
$5\cdot17 - 5 = 85 - 5 = 80 \checkmark$

LaTeX source of the formulas on this page

\[ 5x - 5 = 80\ \Rightarrow\ x = 17 \]
\[ 5x - 5 = 80 \]
\[ 5x - 5 + 5 = 80 + 5 \ \Rightarrow\ 5x = 85 \]
\[ \frac{5x}{5} = \frac{85}{5} \ \Rightarrow\ x = 17 \]
\[ 5\cdot17 - 5 = 85 - 5 = 80 \checkmark \]

Trying values of x in 5x − 5 = 80

x	5x − 5	Equals 80?
15	70	no
16	75	no
17	80	yes
18	85	no
19	90	no

Questions

What is x in 5x − 5 = 80?

The solution of 5x − 5 = 80 is x = 17.

How do you solve 5x − 5 = 80?

Add 5 to both sides to get 5x = 85, then divide both sides by 5 to get x = 17.

How do I check the answer?

Replace x by 17: 5(17) − 5 = 80, which is 80.

Solve 5x − 5 = 80

How to work it out

Trying values of x in 5x − 5 = 80

Questions

Similar equations