Respuesta :

Tucon
   
we use:   a² - b² = (a + b)(a + b)

4(b - 2)² - 9 =

= 2²(b - 2)² - 3^2 =

= [2(b - 2)]² - 3^2 =

= (2(b - 2) + 3)(2(b - 2) - 3)

= (2b - 4 + 3)(2b - 4 - 3)

= (2b - 1)(2b - 7)

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