Question

2. Find the product.
(1) (5 - 2x) (3 + x)
(iii) (a + b)(a + b)​

Answer 1

Answer:

(5-2x)(3+x)

15+5x-6x-2x²

-2x²-x+15

(a+b)(a+b)

a²+ab+ba+b²

a²+2ab+b²

Answer 2

(i)

$(5 - 2x)(3 + x) \\ 5(3 + x) - 2x(3 + x) \\ 15 + x - 6x - 2 {x}^{2} \\ 15 - 5x - 2 {x}^{2} \\ {x}^{2} \: must \: not \: be \: negative \\ so \: 15 - 5x - 2 {x}^{2} = 0 \\ 15 - 5x = 2 {x}^{2} \\ 15 = 2 {x}^{2} + 5x \\ 0 = 2 {x}^{2} + 5x - 15 \\ 2 {x}^{2} + 5x - 15$

(ii)

$(a + b)(a + b) \\ a(a + b) + b(a + b) \\ {a}^{2} + ab + ba + {b}^{2} \\ {a}^{2} + ab + ab + {b}^{2} \\ {a}^{2} + 2ab + {b}^{2}$