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Descompuneti in factori:
1. 2x^2+x-1
2. 3x^2+x-2
3. 2x^2+x-3
4. 2x^2+3x+1
5. 2x^2-x-3
6. 3x^2-x-2

P.S. (^2 este la patrat)


Răspuns :

1) x^2 +x^2+x-1=x^2 +x+x^2-1=x(x+1) +(x+1)(x-1)=(x+1)(x+x-1)=(x+1)(2x-1)

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

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

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

5) 2x^2-x-3=3x^2=x^2-x-3=3x^2-3-x^2-x=3(x^2-1)-(x^2+x)
3(x+1)(x-1)-x(x+1)=(x+1)(3x-3-x)=(x+1)(2x-3)

6)3x^2-x-2=2x^2+x^2-x-2=2x^2-2-x^2-x=2(x^2-1)-x(x-1)=
2(x+1)(x-1)-x(x-1)=(x-1)(2x+2-x)=(x-1)(x+2)