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Dezvoltati fiecare produs, utilizand formulele de calcul prescurtat:

a) (x+1) la puterea a 2 =

b) (x-2) la puterea a 2 =

c) (2x+3) la puterea a 2=

d) (3x-1) la puterea a 2=

e) (3x-1)(3x+1)=


Răspuns :

[tex]\it Folosim\ formulele: \\ \\ (a\pm b)^2=a^2\pm2ab+b^2\\ \\ (a-b)(a+b)=a^2-b^2\\ \\ \\ a)\ (x+1)^2=x^2+2\cdot x\cdot1+1^2=x^2+2x+1\\ \\ b)\ (x-2)^2=x^2-2\cdot x\cdot2+2^2=x^2-4x+4[/tex]

[tex]\it c)\ (2x+3)^2=(2x)^2+2\cdot2x\cdot3+3^2=4x^2+12x+9\\ \\ d)\ (3x-1)^2=(3x)^2-2\cdot3x\cdot1+1^2=9x^2-6x+1\\ \\ \\ e)\ (3x-1)(3x+1)=(3x)^2-1^2=9x^2-1[/tex]