(2a + 3b + c) + (a + 3b + -4c) =?

Use the procedure indicated in your previous post.

but how do u do it? how do i solve it?

To simplify the given expression (2a + 3b + c) + (a + 3b + -4c), we need to combine like terms. Like terms are terms that have the same variables raised to the same powers.

Step 1: Group the like terms together:
(2a + a) + (3b + 3b) + (c + -4c)

Step 2: Combine the like terms within each group:
3a + 6b + -3c

Therefore, the simplified expression is 3a + 6b - 3c.