Question

if x+y = 8 and xy = 30/2 find 3(x^2 + y^2)​

Answer 1

this is your ans with proof

Answer 2

$x + y = 8 \\ xy = \frac{30}{2}$

$xy = 15$

so

x=15/y

then,

15/y + y=8

$\frac{15 + {y}^{2} }{y } = 8$

${y}^{2} + 15 = 8y \\ {y}^{2} - 8y + 15 = 0 \\ {y}^{2} - 3y - 5y + 15 = 0 \\ {y}(y - 3) - 5(y - 3) \\ (y - 3)(y - 5) \\ y = 3 \\ or \: \\ y = 5$

$x = \frac{15}{y} \\ x = \frac{15}{5} = 3 \\ or \\ x = \frac{15}{3} = 5$

then,

$3( {x}^{2} + {y}^{2} ) \\3( {5}^{2} + {3}^{2} ) \\ 3(25 + 9) \\ 3 \times 34 = 102$

hence it is 102

pls. mark BRAINLIEST.