Question

x+y=5
xy=6
a) (x+y)²=?
b) x²+y²=13
c) a=(x-y)²+ 1/x+1/y​

Answer 1

Explicație pas cu pas:

xy=6=>2xy=12

(x+y)²=5²=25

(x+y)²=x²+2xy+y²=25 =>x²+y²=25-12 =>

x²+y²=13

(x-y)²+1/x+1/y=x²-2xy+y²+y/xy +x/xy =

13-12+(x+y)/xy=1+5/6 =11/6