Question

The sum of two real numbers is 18 and the product is 70. what are the two numbers?

Answer 1

let the numbers be x and y:
x+y=18......i
xy=70.........ii
from i
y=18-x.....iii
from ii
y=70/x......iv
substituting iii in iv we get:
70/x=18-x
multiplying through by x;
70=18x-x^2
x^2-18x+70=0
x=12.3 or 5.7
thus:
x=12.3 and y=5.7