Question

Resuelve las siguientes ecuaciones:
(b+3)(b-2)=36





2a²-1=(b-3)(b+3)+17



(a-2)(3a+4)-2a(5a+1)=a-8

Answer 1

a) ( b + 3 ) ( b - 2 ) = 36
b² - 2b + 3b - 6 = 36
b² - b - 6 - 36 = 0
b² - b - 42 = 0
( b - 7 ) ( b + 6 ) = 0
b - 7 = 0 ; b + 6 = 0
b = 7 ; b = - 6

B) 2a² - 1 = ( b - 3 ) ( b + 3 ) + 17
2a² - 1 = b² - 9 + 17
2a² - 1 = b² + 8
2a² - b² = 8 + 1
2a² - b² = 9
a² = 9 + b²
a = √( 9 + b² )

C) ( a - 2 ) ( 3a + 4 ) - 2a ( 5a + 1 ) = a - 8
3a² + 4a - 6a - 8 - 10a² - 2a = a - 8
3a² - 10a² - 4a - 8 + 8 - a = 0
- 7a² - 5a = 0
-a ( 7a + 5 ) = 0
- a = 0 ; 7a + 5 = 0
a = 0 ; a = -5/7