Question

Efetue(x+3)(x/2-5x+6)

Answer 1

$(x+3)(\frac{x}{2} -5x+6)~~~~~~~propriedade~distributiva:\\ \\ \frac{x^{2} }{2} -5x^{2} +6x+\frac{3x}{2} -15x+18\\ \\ m.m.c.=2\\ \\ \frac{x^{2}-10x^{2}+12x+3x-30x+36  }{2} \\ \\ -9x^{2} -15x+36=0$

Δ = b² - 4.a.c

Δ = -15² - 4.(-9).36

Δ = 225 + 1296

Δ = 1521

$x=\frac{-b+-\sqrt{delta} }{2.a} \\ \\ x=\frac{15+-\sqrt{1521} }{-18} \\ \\ x=\frac{15+-39}{-18} \\ \\ x'=\frac{15+39}{-18} =\frac{54}{-18} =-3\\ \\ x''=\frac{15-39}{-18} \\ \\ x''=\frac{-24}{-18} =+\frac{4}{3} \\ \\ (x'=-3;~~~~x''=\frac{4}{3} )$