Question

sistema 2x+2y=20 e x.y=24

Answer 1

2.(x+y) = 20
x+y = 20/2
x+y = 10 --> y = 10-x
xy = 24

x.(10-x) = 24
-x²+10x-24 = 0 .(-1)
x²-10x+24 = 0
/\ = (-10)² - 4.1.24
/\ = 100 - 96
/\ = 4
x = (-(-10)+/- \/4)/2
x = (10+/-2)/2
x' = 12/2 = 6
x" = 8/2 = 4