Verified answer

Ответ:

Объяснение:

x1+x2= -7

x1*x2= -15

5(x1+x2)-3x1x2= 5*(-7)+3*15= 10

х²+7х-15=0

D=49+60=109

х1=-7-√109/2

х2=-7+√109/2

5х1+5х2-3х1х2 = 5×(-7-√109/2) + 5×(-7+√109/2) - 3(-7-√109/2)(-7+√109/2) = (-35-5√109)/2 + (-35+5√109)/2 + 45 = (-35-5√109-35+5√109+90)/2 = 20/2 = 10