Răspuns :
(2x−5)² + 3(x-2)(x+2) -(x+4)² =
(2x-5) (2x-5) + (3x-6)(x+2)-(x+4)(x+4)=
4x²−20x+25 +(3x²−12) -( x²+8x+16)=
= 4x² −20x +25 +3x² −12 −x²−8x -16 =
= 6x² −28x -3
(2x−5)² + 3(x-2)(x+2) -(x+4)² =
(2x-5) (2x-5) + (3x-6)(x+2)-(x+4)(x+4)=
4x²−20x+25 +(3x²−12) -( x²+8x+16)=
= 4x² −20x +25 +3x² −12 −x²−8x -16 =
= 6x² −28x -3