79)
-5(3a+2b-6c)
you just distribute the -5 to what's in the parentheses.
-15a-10b+30c
80)
-1(a-3b+x-y)
since there is a negative infront you distribute that negative to what's in the parentheses.
-a+3b-x+y
81)
3(x^2-y)
distribute the 3.
3x^2-3y
83)
3(2a-3b)
distribute the 3.
6a-9b
82)
-9(2x^2-3y)
distribute the -9
-18x^2+27y
84)
-(-2x+3y-6z)
distribute the negative
2x-3y+6z
