Question

Subtract:

5a + 7b − 2c from 3a − 7b + 4c

Answer 1

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

Term to be subtracted = 5a + 7b − 2c
 Changing the sign of each term of the expression gives -5a -7b + 2c.
 On adding:
(3a − 7b + 4c)+(-5a -7b + 2c ) = 3a − 7b + 4c-5a -7b + 2c
= (3-5)a+( − 7-7)b + (4+2)c
= -2a − 14b + 6c