Question

use suitable identities to find the following products :
$a).(2x + 7)(3x - 5)$
$b).(4x + 5)(2x - 7)$
$c).(3 - 2x)(2 + 3x)$

Answer 1

$a.(2x + 7)(3x - 5) \\ 6 {x}^{2} - 10x + 21x - 35 \\ 6 {x}^{2} + ( - 10x + 21x) - 36 \\ 6 {x}^{2} + 11x - 35 \\ \\ b.(4x + 5)(2x - 7) \\ 8 {x}^{2} - 28x + 10x - 35 \\ 8 {x}^{2} + ( - 28x + 10x) - 35 \\ 8 {x}^{2} - 18x - 35 \\ \\ c.(3 - 2x)(2 + 3x) \\ 6 + 9x - 4x - 6 {x}^{2} \\ 6 + (9x - 4x) - 6 {x}^{2} \\ 6 + 5x - 6{x}^{2}$
use the FOIL method: (a+b)(c+d)=ac+ad+bc+bd

Answer 2

Answer:

Step-by-step explanation:

a.(2x + 7)(3x - 5) \\ 6 {x}^{2}  - 10x + 21x - 35 \\ 6 {x}^{2}  + ( - 10x + 21x) - 36 \\ 6 {x}^{2}  + 11x - 35 \\  \\ b.(4x + 5)(2x - 7) \\ 8 {x}^{2} - 28x + 10x - 35 \\ 8 {x}^{2} + ( - 28x  + 10x) - 35  \\ 8 {x}^{2} - 18x - 35 \\  \\ c.(3 - 2x)(2 + 3x) \\ 6 + 9x - 4x - 6 {x}^{2}  \\ 6 + (9x - 4x) - 6 {x}^{2}  \\ 6 + 5x -  6{x}^{2}  

use the FOIL method: (a+b)(c+d)=ac+ad+bc+bd