Question

Descompuneti in factori:
a) x²-3x-4
c) x²-6x-27
e)x²+7x-18
g)x²+3x-4
i)x²-5x-6
k)x²+5x-6
m)²-3x-10
o)x²-13x-14
VA ROG DIN SUFLET! CAT PUTETI!

Answer 1

a) x²-3x-4 =x²- 4x+1x - 4= x(x-4)+1(x-4)=(x-4)(x+1)

c) x²-6x-27=x²-3x+9x-27=x(x+9)- 3(x+9)=(x-9)(x+3)

e)x²+7x-18= x² + 9x - 2x -18 = x(x+9) - 2(x+9) = (x+9)(x-2)

g)x²+3x-4=x²-3x-4=x²-x+4x-4=(x-1)(x+4)

i)x²-5x-6= x² - 3x - 2x + 6 =(x - 2)(x - 3)

k)x²+5x-6=x²-x+6x-6=x(x+6)-(x+6)=(x + 6)(x - 1)

m)x²-3x-10=x²+2x-5x-10=x(x-5)+2(x-5)=(x+2)(x-5)

o)x²-13x-14=x²+x-14x-14=x(x-14)+(x-14)=(x-14)(x+1)

Answer 2

a)x^2-4x+x-4=x(x-4)+(x-4)=(x-4)(x+1)
c)delta=(-6)^2-4•(-27)=36+108=144 => radical din delta = 12
x1=(6-12)/2=-3
x2=(6+12)/2=9
(x+3)(x-9)
e)delta=49-4•(-18)=49+72=121 => radical din delta = 11
x1=(-7-11)/2=-9
x2=(-7+11)/2=2
(x-2)(x+9)
g)x^2+4x-x-4=x(x+4)-(x+4)=(x+4)(x-1)
i)x^2-6x+x-6=x(x-6)+(x-6)=(x-6)(x+1)
k)x^2+6x-x-6=x(x+6)-(x+6)=(x+6)(x-1)
m)delta=(-3)^2-4•(-10)=9+40=49 => radical din delta = 7
x1=(3-7)/2=-2
x2=(3+7)/2=5
(x-5)(x+2)
o)x^2-14x+x-14=x(x-14)+(x-14)=(x-14)(x+1)