Question

valor numerico da expressões

y4 - 3X Y³ +7X² Y²-2X³ Y,para 1/2 y=-2

Answer 1

$y*4-3*x* y^{2} +7* x^{2} * y^{2} -2 x^{3}=$
$(-2)*4-3* \frac{1}{2}*(-2) ^{2}+7* (-2)^{2}* (\frac{1}{2})^{2}-2*(\frac{1}{2})^{3}$
$-8- \frac{3}{2} *4+7*4* \frac{1}{4}-2* \frac{1}{8}$
$- \frac{1}{8}- \frac{12}{2}+ \frac{28}{4}- \frac{2}{8}=\frac{-64-48+56-2}{8}= \frac{58}{8}=\frac{29}{4}$