(4x - 1) (2x + 3) = (x + 3)(x - 1)?

(4x - 1)(2x + 3) = (x + 3)(x - 1)

(4x)(2x) + (4x)(3) - (2x)(1) - (3)(1) = (x)(x) - (x)(1) + 3(x) - 3(1)

8x² + 12x - 2x - 3 = x² - x + 3x - 3

8x² + 10x - 3 = x² + 2x - 3

8x² + 10x = x² + 2x

8x² - x² = 2x - 10x

7x² = - 8x

7x² + 8x = 0

x(7x + 8) = 0 x = 0 ; x = - 8 / 7 comprobando : la igualdad se da con x = 0

espero que se entienda xD.