(a4-6a+5)-(a4-3a+4a-6)
by expressing like term
a4-a4=0
-6a-(-3a+4a)=-5a
5-(-6)=11
:we have-5a+11
1 → B
multiply each term in the parenthesis by the 6 outside
6(b-7) = 6b - 42
2 → D
multiply each term in the parenthesis by the 3 outside
3(4x+6y+2) = 12x+18y+6
3 → A
the value outside the parenthesis is -1, hence each term inside is multiplied by -1
-1(6x+5y) = -6x -5y