Question

The product of two numbers is 800 and their sum is 90. what are the numbers?

Answer 1

Answer:

X,Y be the number

XY =800

X+Y =90

(X +Y)(X +Y )=X^2+Y^2+2XY

90*90=x^2+y^2+2×800

8100-1600=X^2+Y^2

6500=X^2+Y^2

(X-Y)^2=X^2+Y^2+2XY

X+Y(X-Y)^2=6500+1600

(X-Y)^2=8100

X-Y=√8100

X - Y= 9×10

X - Y = 90

X+Y=90

X-Y=90

2X=180

X=90

Y= 0