besoin d'aide en mathématiques pls​

Réponse:

Bonsoir,

a)

[tex](x + 5) {}^{2} = x {}^{2} + 10x + 25[/tex][/tex]

b)

[tex](y - 1) {}^{2} = y { }^{2} - 2y + 1[/tex]

c)

[tex](z + 4) {}^{2} = z {}^{2} + 8z + 16[/tex]

d)

[tex](n + 7)(n - 7) = n {}^{2} - 49[/tex]

e)

[tex](3x + 4) {}^{2} = 9x {}^{2} + 24x + 16[/tex]

f)

[tex](4x - 5) {}^{2} = 16x {}^{2} - 40x + 25[/tex]

Exercice 9:

[tex]21 {}^{2} = (20 + 1) {}^{2} = 400 + 40 + 1 = 441[/tex]

[tex]19 { }^{2} = (10 + 9) {}^{2} = 100 + 180 + 81 = 361[/tex]

[tex]19 \times 21 = (20 - 1)(20 + 1) = 400 - 1 = 399[/tex]

[tex]89 {}^{2} = (80 + 9) {}^{2} = 1600 + 1440 + 81 = 7921[/tex]

[tex]91 {}^{2} = (90 + 1) {}^{2} = 8100 + 180 + 1 = 8281[/tex]

[tex]91 \times 89 =( 90 + 1)(90 - 1) = 8100 - 1 = 8099[/tex]

[tex]199 {}^{2} = (200 - 1) {}^{2} = 40000 - 400 + 1 = 39601[/tex]