Question

已知数m,x,y满足①4/3(x-5)^2+5|m|=0;②-3a^2b^(y+1)与4b^3a^2是同类项,求多项式2

Answer 1

已知数m,x,y满足①4/3(x-5)^2+5|m|=0;②-3a^2b^(y+1)与4b^3a^2是同类项

所以x-5=0,m=0,y+1=3

所以x=5,y=2,m=0

所以2x^2-6y^2+m（xy-9y^2）-(3x^2-3xy+7y^2)

=2*5^2-6*2^2+0*（xy-9y^2）-(3*5^2-3*5*2+7*2^2)

=50-24-(75-30+28)

=26-73

=-47