Question

Упростите выражение 7b(2b+3)-(b+6)(b-5)​

Answer 1

$7b(2b + 3) - (b + 6)(b - 5) = 14 {b}^{2} + 21b - ( {b}^{2} - 5b + 6b - 30) = 14 {b}^{2} + 21b - {b}^{2} + 5b - 6b + 30 = 14 {b}^{2} - {b}^{2} + 21b + 5b - 6b + 30 = \boldsymbol{13 {b}^{2} + 20b + 30}$

Answer 2

Решение:

7b · (2b + 3) - (b + 6) · (b - 5)​ =

= 14b² + 21b - (b² + b - 30) =

= 14b² + 21b - b² - b + 30 =

= 13 b² + 20b + 30