Question

已知m,x,y满足：1.2\3（x-5）^2+5|m|=0; 2.-2a^2b^y+1与7b^

Answer 1

2/3(x-5)^2+5*(m的绝对值)=0吧?如果是

因为2/3(x-5)^2+5*(m的绝对值)=0,所以2/3(x-5)^2=0,5*(m的绝对值)=0,即：x-5=0,x=5,m=0

以为2a^2b^(y+1)与7b^3a^2是同类项,所以y+1=3,y=2

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)=50-24-0-(75-30+28)=-47