Question

Sabendo que ( x + y )² = 150 e xy = 18, determine o valor de ( x² + y² )?

Answer 1

$(x + y) {}^{2} = 150$

$x {}^{2} + 2xy + y {}^{2} = 150$

$(x {}^{2} + y {}^{2} )= 150 - 2xy$

$(x {}^{2} + y {}^{2} ) = 2(75 - 18)$

$(x {}^{2} + y {}^{2} ) = 114$