Question

The sum of two numbers is equal to 70. Which of the following functions can be use to find the product of the two numbers if one of the numbers is x?

a) p = x^2

b) p = x (x-70)

c) p = x (70 - x)

d) p = (x - 70)^2

Answer 1

Let x=number 1 let y=number2
there sum is equal to 70
then

number1+number2=70

substituting

x+y=70

y=70-x
let there product will be p
p=xy
substituting
p=x(70-x)
which is choice c