Question

Descompuneti în factori:
1. x^2-1=
2. 9x^2-4y^2=
3. a^2-7=
4. 2x^2-5=
5. (x+2)^2-1=

Answer 1

1) x²-1=(x+1)(x-1) Proba: (x+1)(x-1)=x²-1²=x²-1
2) 9x²-4y²=(3x+2y)(3x-2y) Proba: (3x+2y)(3x-2y)=(3x)²-(2y)=9x²-4y²
3) a²-7=(a+√7)(a-√7) Proba: (a+√7)(a-√7)=a²-√7²=a²-√49=a²-7                                 4) 2x²-5=(√2x+√5)(√2x-√5) Proba: (√2x-√5)(√2x+√5)=√2x²-√5²=2x²-5
5) (x+2)²-1=(x+2-1)(x+2+1)=(x+1)(x+3)
 
Formula aplicata: Formula diferentelor de patrate ,, (a+b)(a-b)=a²-b² ''.

Mult noroc!