Объяснение:
1.(-2/7м+7б)^2=-4/49м^2-4мб+49б^2
2.(-1/4р+2/5р)^2=(-5/20р+8/20р)^2=(3/20)^2=
9/400
3.(-6/7с+7/10б)^2=36/49с^2-1,2сб+49/10б^2
Объяснение:
1.(-2/7м+7б)^2=-4/49м^2-4мб+49б^2
2.(-1/4р+2/5р)^2=(-5/20р+8/20р)^2=(3/20)^2=
9/400
3.(-6/7с+7/10б)^2=36/49с^2-1,2сб+49/10б^2