Răspuns:
[tex]a) {(x + 7)}^{2} = {x}^{2} + 2 \times x \times 7 + {7}^{2} = {x}^{2} + 14x + 49[/tex]
[tex]b) {(2x - 5)}^{2} = ( {2x})^{2} - 2 \times 2x \times 5 + {5}^{2} = 4 {x}^{2} - 20x + 25[/tex]
[tex]c)( {3x - 1})^{2} = (3 {x})^{2} - 2 \times 3x \times 1 + {1}^{2} = 9 {x}^{2} - 6x + 1[/tex]
[tex]d)( {4x + 3})^{2} = (4 {x})^{2} + 2 \times 4x \times 3 + {3}^{2} = 16 {x}^{2} + 24x + 9[/tex]
[tex]e)( {2x - 7y})^{2} = (2 {x})^{2} - 2 \times 2x \times 7y + (7 {y})^{2} = 4 {x}^{2} - 28xy + 49 {y}^{2} [/tex]
[tex]f)( {3x + 4y})^{2} = (3 {x})^{2} + 2 \times 3x \times 4y + (4 {y})^{2} = 9 {x}^{2} + 24xy + 16 {y}^{2} [/tex]
[tex]g)( {2a - 5b})^{2} = (2 {a})^{2} - 2 \times 2a \times 5b + 5 {b}^{2} = 4 {a}^{2} - 20ab + 25 {b}^{2} [/tex]
[tex]h)( {3x - 2y})^{2} = (3 {x})^{2} - 2 \times 3x \times 2y + (2 {y})^{2} = 9 {x}^{2} - 12xy + 4 {y}^{2} [/tex]
[tex]i)( {2 - 5x})^{2} = {2}^{2} - 2 \times 2 \times 5x + (5 {x})^{2} = 4 - 20x + 25 {x}^{2} = 25 {x}^{2} - 20x + 4[/tex]
[tex]j)( {4x + y})^{2} = (4 {x})^{2} + 2 \times 4x \times y + {y}^{2} = 16 {x}^{2} + 8xy + {y}^{2} [/tex]
[tex]k)( {3 - x})^{2} = {3}^{2} - 2 \times 3 \times x + {x}^{2} = {x}^{2} - 6x + 9[/tex]
[tex]l)( {3c - 7})^{2} = (3 {c})^{2} - 2 \times 3c \times 7 + {7}^{2} = 9 {c}^{2} - 42c + 49[/tex]
