计算:(x-2y)^2 ...(-m+2n)^2 ...(a-3b)^2 ...(-x-1/2 y)^2...(3x)^
2个回答

(x-2y)²

=x²-2×x×2y+(2y)²

=x²-4xy+4y²

(-m+2n)²

=(-m)²-2×m×2n+(2n)²

=m²-4mn+4n²

(a-3b)²

=a²-2×a×3b+(3b)²

=a²-6ab+9b²

(-x-1/2y)²

=(x+1/2y)²

=x²+2×x×1/2y+(1/2y)²

=x²+xy+1/4y²

(3x)³×(x²)^5-(x^5×x³)²

=3³×x³×x^10-x^10×x^6

=27x^13-x^16

4^2007×0.25^2008

=4^2007×0.25^2007×0.25

=(4×0.25)^2007×0.25

=1^2007×0.25

=1×0.25

=0.25