Question

subtract (2a-3b+4c) from the sum of (a+3b-4c)(4a-b+9c) and (-2b+3c-a)

Answer 1

a+3b-4c+4a-b+9c-2b+3c-a-(2a-3b+4c)
=4a+8c-2a+3b-4c
=2a+3b+4c

Answer 2

Step-by-step explanation:

First find the sum of all terms

$a + 3b - 4c \\ \\ 4a - b + 9c \\ \\ - a - 2b + 3c \\ \\ sum \: of \: all \: terms = \\ a + 4a - a + 3b - b - 2b - 4c + 9c + 3c \\ \\ = 4a + 8c$

Now subtract

$= 4a + 8c - (2a - 3b + 4c) \\ \\ = 4a - 2a + 3b + 8c - 4c \\ \\ = 2a + 3b + 4c$

Hope it helps you.