What is the simplest form of this expression? (x + 7)(3x − 8) A. 3x2 + 2x − 15 B. 3x2 + 29x − 1 C. 3x2 − 29x − 56 D. 3x2 + 13x –

Question

Andreyy89

3 years ago

12

What is the simplest form of this expression? (x + 7)(3x − 8) A. 3x2 + 2x − 15 B. 3x2 + 29x − 1 C. 3x2 − 29x − 56 D. 3x2 + 13x –

56

Mathematics

2 answers:

shepuryov [24] · Answer 1 · 2022-07-31T05:26:11+03:00

shepuryov [24]3 years ago

4 0

Answer:

$\boxed{\sf D. \ 3 {x}^{2} + 13x - 56}$

Step-by-step explanation:

$\sf Expand \: the \: following: \\ \sf \implies (x + 7)(3x - 8) \\ \\ \sf \implies x(3x - 8) + 7(3x - 8) \\ \\ \sf \implies (x)(3x) - (x)(8) + (7)(3x) - (7)(8) \\ \\ \sf (x)(3x) = 3 {x}^{2} : \\ \sf \implies \boxed{ \sf 3 {x}^{2}} - 8x + (7)(3x) - (7)(8) \\ \\ \sf 7 \times 3 = 21 : \\ \sf \implies 3 {x}^{2} - 8x + \boxed{ \sf 21}x - (7)(8) \\ \\ \sf 7 \times 8 = 56 : \\\sf \implies 3 {x}^{2} - 8x + 21x - \boxed{ \sf 56} \\ \\ \sf 21x - 8x = 13x : \\ \sf \implies 3 {x}^{2} + 13x - 56$