Question

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

Answer 1

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.