Answer:
65
Step-by-step explanation:
let the son's age be x then the man's age is 5x
In 13 years
son's age = x + 13 and man's age = 5x + 13 and he is 3 times as old as son
5x + 13 = 3(x + 13)
5x + 13 = 3x + 39 ( subtract 3x from both sides )
2x + 13 = 39 ( subtract 13 from both sides )
2x = 26 ( divide both sides by 2 )
x = 13 ← son's present age
5x = 5 × 13 = 65 ← man's present age
-72/12=-6
Because 12×(-6)=-72
Multiply -3 to x and get -3x and multiply 4 and -3 and get -12 so then subtract -12 and 15 and get -3 so now it is -3x-3=6-4y so now. You subtract -3 and 6 and get positive 3 so now the final answer is -3x-4y+3