已知x(3次方)y(m-1次方)×(乘以)x(m+n次方)y(2n+2次方)=x(九次方)y(九次方)
问题描述:
已知x(3次方)y(m-1次方)×(乘以)x(m+n次方)y(2n+2次方)=x(九次方)y(九次方)
继续上面的:则4m-3n等于
A.8 B.9 C.10 D.11
答
∵x(3次方)y(m-1次方)×(乘以)x(m+n次方)y(2n+2次方)=x(九次方)y(九次方)
∴x^(m+n+3)·y^(m+2n+1)=x^9·y^9
∴m+n+3=6,m+2n+1=9
∴m=4,n=2
∴4m-3n=10
选C