Question

How much is a + 2a − 3c greater than 2a − 3b + c?

Answer 1

To calculate how much is a + 2b − 3c greater than 2a − 3b + c, we have to subtract 2a − 3b + c from a + 2b − 3c.

Change the sign of each term of the expression that is to be subtracted and then add.

Term to be subtracted = 2a − 3b + c
Changing the sign of each term of the expression gives -2a + 3b - c.
On adding:
(a + 2b − 3c )+(-2a + 3b - c )
= a + 2b − 3c -2a + 3b - c
= (1-2)a + (2+3)b +(− 3-1)c
= -a + 5b − 4c