Find the expression to be added with 5a – 3b – 2c to get a – 4b

1.	Find the expression to be added with 5a – 3b – 2c to get a – 4b – 2c?
Answer» To get the required expression we must subtract 5a – 3b + 2c from a – 4b – 2c. ∴ a – 4b – 2c – (5a – 3b + 2c) = a – 4b – 2c + (- 5a + 3b – 2c) = a – 4b – 2c – 5a + 3b - 2c = (1 – 5) a + (- 4 + 3) b + (- 2 – 2) c = – 4a – b – 4c. ∴ -4a – b – 4c must be added.

Find the expression to be added with 5a – 3b – 2c to get a – 4b – 2c?

Answer»

To get the required expression we must subtract

5a – 3b + 2c from a – 4b – 2c.

∴ a – 4b – 2c – (5a – 3b + 2c) = a – 4b – 2c + (- 5a + 3b – 2c)

= a – 4b – 2c – 5a + 3b - 2c

= (1 – 5) a + (- 4 + 3) b + (- 2 – 2) c

= – 4a – b – 4c.

∴ -4a – b – 4c must be added.