Question

please solve this urgent
1.(x + 1) (3 - x)
2.(5 - x) (X + 8)
find by inspection the efficient of X in the following expansion​

Answer 1

Step-by-step explanation:

(x + 1) (3 - x)

3x-x²+3-x

-x²+2x+3

(5-x)(X+8)

5x+40-x²-8x

-x²-3x+40

that's all,,

Answer 2

$i) \: \: \: \: (x + 1)(3 - x) \\ \\ = x(3 - x) + 1(3 - x) \\ \\ = 3x - {x}^{2} + 3 - x \\ \\ = {x}^{2} + 3x + x + 3 \\ \\ = {x}^{2} + 4x + 3 \\ \\ so \: \: \: the \: \: \: coefficient \: \: \: of \: \\ x \: \: \: = \: \: \: 4 \\ \\ \\ ii) \: \: \: (5 - x)(x + 8) \\ \\ = 5(x + 8) - x(x + 8) \\ \\ = 5x + 40 - {x}^{2} - 8x \\ \\ = - {x}^{2} + 5x - 8x + 40 \\ \\ = - {x}^{2} - 3x + 40 \\ \\ so \: \: \: the \: \: \: coefficient \: \: \: of \\ x = - 3$