Question

计算题.1、 0.3m^2n-5分之1mn^2+0.4n^2m-m^2n-2分之1nm^2

Answer 1

(1)

0.3m^2n-5分之1mn^2+0.4n^2m-m^2n-2分之1nm^2

=(0.3-1-2分之1)m^2n + (0.4-5分之1)mn^2

= -1.2m^2n + 0.2mn^2

=0.2mn^2 -1.2m^2n

(2)

-3分之1（9x^2-3）+6（3分之2x^2+1）

= -3分之1*9x^2+3分之1*3+6*3分之2x^2+6

= -3x^2+1+4x^2+6

=x^2+7