Question

Simplify combining the like terms: (i) a – (a – b) – b – (b – a) (ii) x^2 – 3x + y^2 – x – 2y^2

Answer 1

Answer:

$(i)a - b$

$(ii) {x}^{2} - 4x - {y}^{2}$

Step - by - step explanation:

$(i)a - (a - b) - b - (b - a)$

$= a - a + b - b - b + a$

$= (a - a + a) + (b - b - b)$

$= (1 - 1 + 1)a \: + \: (1 - 1 - 1)b$

$= 1a + ( - 1b)$

$= 1a - 1b$

$= a - b$

$(ii) {x}^{2} - 3x + {y}^{2} - x - 2 {y}^{2}$

$= {x}^{2} + ( - 3x - x) + ( {y}^{2} - 2 {y}^{2} )$

$= {x}^{2} + ( - 3 - 1)x + (1 - 2) {y}^{2}$

$= {x}^{2} + ( - 4x) + ( - 1 {y}^{2} )$

$= {x}^{2} - 4x - {y}^{2}$