Answer :
let's just start with x=20 and then do some algebra to it to make it all complicated
x = 20
2 * x = 2 * 20
2x = 40
2x - 13 = 40 - 13
2x - 13 = 27
x = 20
2 * x = 2 * 20
2x = 40
2x - 13 = 40 - 13
2x - 13 = 27
