Answer:
D
Explanation:
When doing distributive property, you have to multiply the outside number by all of the inside numbers
so 3(6 - 7a), you would have to do 3*6 and 3*-7a and then you would add those two values:
So in this case, you would do 18 + (-21a) which is just 18 - 21a.
Just to help you visualize distributive property better
3(6+8) = 3*6 + 3*8
4(20+5+3) = 4*20 + 4*5 + 4*3
10(15.5 - 24.4 + 23.21) = 10*15.5 + 10*(-24.4) + 10*23.21
I hope this helped, let me know if you have any questions