Question

Descompuneti in factori,daca e posibil,expreia:x la puterea 2-10x+21,-2x la puterea 2+3x+2

Answer 1

Răspuns:

x^2 - 3x - 7x + 21 = x(x-3) - 7(x-3) =

(x-3)(x-7)

-2x^2 + 3x + 2 = 0

delta = 3^2 - 4•(-2)•2 = 9+16 = 25 =>rad.delta = 5

x1=(-3-5)/2•(-2)=2

x2=(-3+5)/2•(-2)=(-1/2)

(x + 1/2)(x-2)