Question

4(3x+8y)-5(2x-6y)

Answer 1

4(3x+8y)-5(2x-6y)

=12x+32y-10x+30y

=2x+62y

(m +n)-[3m+(-m+n)]

=m+n-3m-(-m+n)

=m+n-3m+m-n

=-m

当a=-5 b=0.5时 求代数式a-2(2a+b)+3(a-b)的值

原式=a-4a-2b+3a-3b=-5b=-5*0.5=-2.5

已知A=5x+3y-2 B=2x-2y+3

求A+B

求A-2B

A+B=5x+3y-2+2x-2y+3=7x+y+1

A-2B=5x+3y-2-4x+4y-6=x+7y-8