Bonjour,
[tex]x(x + 2) = x \times x + x \times 2 = {x}^{2} + 2x[/tex]
[tex]x(x - 6) = x \times x - 6 \times x = {x}^{2} - 6x [/tex]
[tex]3x(x + 5) = 3x \times x + 3x \times 5 = 3 {x}^{2} + 15x[/tex]
[tex]5x(x - 1) = 5x \times x + 5x \times ( - 1) = 5 {x}^{2} - 5x[/tex]
[tex]6x(2 + 9x) = 6x \times 2 + 6x \times 9x = 12x + 54 {x}^{2} [/tex]
[tex]x( {x}^{2} - 4) = x \times {x}^{2} - 4 \times x = {x}^{3} - 4x[/tex]
