Question

evaluate (x+y)=5 xy=2 x²+y²=?

Answer 1

Here given (x+y) =4 & xy= 2

Here we will find (x²+y²) =????????

(x+y)²= x²+2xy+y²....... Equation (1)

But here given that x+y=4 & xy= 2, then

4²=x²+2(2)+y²

x²+y²= 16-4

Ur answer x²+y²=12

Answer 2

Answer:

$x + y = 5 ...equation \: 1\\ xy = 2...equation \: 2$

$squaring \: on \: both \: sides \: of \: equation \: 1$

${x}^{2} + {y}^{2} + 2xy = 25 \\ {x}^{2} + {y}^{2} = 25 - 2xy$

${x}^{2} + {y}^{2} = 25 - 4 = 21$