Simon is 13 years old
Let x be Simon's age
Thus 4 years ago his age was (x - 4) and 2 years from now his age is (x + 2)
Hence 5(x - 4) = 3(x + 2)
distributing both sides gives
5x-20 = 3x + 6
subtract 3x from both sides of the equation
5x - 3x - 20 = 6
2x - 20 = 6
add 20 to both sides
2x = 6 + 20 = 26
divide both sides by 2
x = = 13
Simon is 13 years old