Question

初一的几道数学题,麻烦高手解决一下!谢谢!

Answer 1

1、原式=a^2-2ab+ab-2b^2-2(a^2-ab+2ab-2b^2)

=a^2-ab-2b^2-2a^2-2ab+4b^2

=-a^2-3ab+2b^2

2、原式=x^3+10x^2+5x-2x^2+7x+15=x^3+8x^2+12x+15

4、S=1/2(4m-2)(2m+1)=(2m-1)(2m+1)=4m^2-1

当 m=2时,S=15

5、⑴S=x^2+(a-x)^2=2x^2-2ax+a^2

⑵S1=2*1/9*a^2-2/3a^2+a^2=7/9a^2

S2=2*1/4*a^2-a^2+a^2=1/2a^2

∵7/9>1/2,∴S1>S2