Question

Find a number which when multiplied by 5 increased by 80

Answer 1

Let the number be x,
Then
x×5=x+80
5x-x=80
4x=80
x=20
Hence the number is 20.

Answer 2

let the number be x
x*5=x+80
5x=x+80
5x-x=80
4x=80
x=20