☺ Salut ☺
On donne :
[tex]A = {(12x + 7)}^{2} - (11 - 5x)(12x + 7)[/tex]
1) Développons A :
[tex]A = {(12x + 7)}^{2} - (11 - 5x)(12x + 7)[/tex]
• Développons [tex]{(12x + 7)}^{2}[/tex] et
[tex](11 - 5x)(12x + 7)[/tex].
✧[tex]\;{(12x + 7)}^{2}[/tex] a la forme de [tex]{(a + b)}^{2} = {a}^{2} + 2ab + {b}^{2}[/tex].
Alors :
[tex]\boxed{A = {12x}^{2} + 2\times 12x\times 7 + {7}^{2} - (11\times 12x + 11\times 7 - 5x \times 12x - 5\times 7)}[/tex]
[tex]\boxed{A = 144{x}^{2} + 168x + 49 - (132x + 77 - 60{x}^{2} - 35x)}[/tex]
[tex]\boxed{A = 144{x}^{2} + 168x + 49 - 132x - 77 + 60{x}^{2} + 35x}[/tex]
[tex]\boxed{A = 144{x}^{2} + 60{x}^{2} + 168x - 132x + 35x - 77 + 49}[/tex]
[tex]\boxed{A = (144 + 60){x}^{2} + (168 - 132 + 35)x - 28 }[/tex]
✅[tex]\boxed{\boxed{A = 204{x}^{2} + 71x - 28}}[/tex]✅
