Question

Пусть х*а=7, х+а=4, вычислите:
х^2-ха+а^2

Answer 1

$left { {{x cdot a=7} atop {x+a=4}} right. \ left { {{xa=7} atop {x^2+2xa+a^2=16}} right. left { {{xa=7} atop {x^2+a^2=2}} right. \ x^2+a^2-xa = 2 -7 = -5$