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Alleteodora
a fost răspuns

(2x+3)^2 - (3x-2)^2 - (4x-5)*(4x+5),va rog!

Răspuns :

[tex](2x+3)^2-(3x-2)^2-(4x-5)(4x+5)= \\ =(2x)^2+2 \cdot 2x \cdot 3+3^2-[(3x)^2-2 \cdot 3x \cdot 2+2^2]-16x^2+25= \\ =4x^2+12x+9-(9x^2-12x+4)-16x^2+25= \\ =4x^2+12x+9-9x^2+12x-4-16x^2+25=-21x^2+24x+30[/tex]