Answer:
-10a + 20b - 30c
Explanation:
(4a - 8b + 12c)(-5/2)
=(4a + - 8b + 12c)(-5/2)
=(4a)(-5/2) + (-8b)(-5/2) + (12c)(-5/2)
=-10a + 20b -30c
(Also Mathpapa is great for this kind of problems and Mathw*y is also a good one I use those two all the time they both saved me so many times)