Question

The product (x) of two numbers is 24 and their sum (+) is 10. What is the value of the largest of the two numbers?

Answer 1

let the two numbers be x and y

From the first sentence,

xy=24

x+y=10

Then make y in equation 2 the subject of the formular and substitute in equation 1

x+y=10

y=10-x

substituting in equation 2

x(10-x)=24

open the bracket

10x-x^2=24

=-x^2+10x=24

Transfer the constant to the left hand side

=-x^2+10x-24=0

Then factorise completely

Look at the photo above