a)
[tex](1 + a + b) {}^{2} = 1 {}^{2} + a {}^{2} + b {}^{2} + 2 \times 1a + 2 \times 1b + 2ab = 1 + a {}^{2} + b {}^{2} + 2a + 2b + 2ab[/tex]
b)
[tex](2x + y + z) {}^{2} = (2x {)}^{2} + y {}^{2} + z {}^{2} + 2 \times 2xy + 2 \times xz + 2yz = 4x {}^{2} + y {}^{2} + z {}^{2} + 4xy + 4xz + 2yz[/tex]
c)
[tex](5 + 4a + 3b) {}^{2} = 5 {}^{2} + (4a) {}^{2} + (3b) {}^{2} + 2 \times 5 \times 4a + 2 \times 5 \times 3b + 2 \times 4a \times 3b = 25 + 16a {}^{2} + 9b {}^{2} + 40a + 30b + 24ab[/tex]
Sper ca intelegi!
☆Mult succes!!☆
