The area of the rectangle and triangle and trapezoid?

What would be the reasons for lines 3 and 4? a. addition property; subtraction property b. addition property; solve c. substitution property; subtraction property d. substitution property; prove

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?

Select the correct answer and solve for y