已知2x-3y=1,则7-6x+9y=
问题描述:
已知2x-3y=1,则7-6x+9y=
答
7-6x+9y
=7-(6x-9y)
=7-3(2x-3y)
=7-3*1
=7-3
=4
答
2x-3y=1
-6x+9y=-3*(2x-3y)=-3*1=-3
-6x+9y+7=-3+7=4
答
7-6x+9y
=7-(2x-3y)*3
=7-3=4
答
7-6x+9y=7-3(2x-3y)
因为2x-3y=1
所以7-6x+9y=7-3=4