Question

How do I solve question 5?

Answer 1

A) x^2 + y^2 = 80
B) x * y = 12

What is x^2 -y^2?
B) x * y = 12
So y = 12 / x
A) x^2 + (12/x)^2 = 80
x^2 + (12/x)^2 = 80
x^2 + (144/x^2) = 80
Multiplying each side by x^2
x^4 + 144 = 80x^2
x^4 -80x^2 + 144 = 0
X = 1.355 (found by trial and error)
Y = 8.85608 (found by trial and error)