Question

imi poate expilca si mie cineva cum calculez descompunerile in factori la mate. ex: 9x^2+12-45=?

Answer 1

[tex]O\ ecuatie\ de\ forma\ :ax^2+bx+c\ se\ descompune\ astfel\ :\\ \bold{ax^2+bx+c=a(x-x_1)(x-x_2)}\\ Deci\ avem: \\ 9x^2+12x-45=0\\ \Delta=144+4\cdot 12\cdot 45\\ \Delta=144+1620\\ \Delta=1764\Rightarrow \sqrt{\Delta}=42\\ x_1=\frac{-12+42}{18}=\frac{5}{3}\\ \\ x_2=\frac{-12-42}{18}=-3\\ Astfel:\boxed{\boxed{9x^2+12x-45=9(x-\frac{5}{3})(x+3)}}[/tex]