Question:
Sum of a – b + ab, b + c – bc and c – a – ac is
(a) 2c + ab – ac – bc
(b) 2c – ab – ac – bc
(c) 2c + ab + ac + bc
(d) 2c – ab + ac + bc
Solution:
(a) 2c + ab – ac – bc
We have,
= (a – b + ab) + (b + c – bc) + (c – a – ac)
= a – b + ab + b + c – bc + c – a – ac
Now, grouping like terms
= (a – a) + (-b + b) + (c + c) + ab – bc – ac
= 2c + ab – bc – ac