So 30/48=15/(x+9) this could be easily solved by recognizing the proportion (the other way is usiing full algebra and doing multiply both sides by 48(x+9) and then divide both sides by 30 then subtract 9) 30 is 2 times of 15 therefor 48 is 2 times of (x+9) 48=2 times (x+9) divide both sides by 2 24=x+9 subtract 9 15=x
