Question

me ajudem pfv
A) ( y - 3 ) . ( y + 2 ) - ( y + 1 )²

B ) ( 9 x + 1 )²- ( y + 9)²

C) ( 2a + 3b)²- 4a ( ab + 3b)

Answer 1

A)
= (y - 3). (y + 2) - (y + 1)²
= y² + 2y - 3y - 6 - [y² - 2y + 1]
= y² - y - 6 - y² + 2y - 1

= - y + 2y - 6 - 1

= y - 7

****************************
B )
= (9x + 1)² - (y + 9)² 

= (9x)² + 2.1.9x + 1² - [y² + 2.9y + 9²]

= 81x² + 18x + 1 - [y² + 18y + 81]

= 81x² + 18x + 1 - y² - 18y - 81

= 81x² - y² + 18x - 18y - 80

****************************************************
C)
= (2a + 3b)² - 4a.(ab + 3b)

= (2a)² + 2.2a.3b + (3b)² - 4a.ab - 4a.3b

= 4a² + 12ab + 9b² - 4a²b - 12ab

= 4a² - 4a²b + 9b²

***********************************