Question

помогите пожалуйста 2 и 3 пж​

Answer 1

Ответ:

2)

a) $x^{2} -81 = (x-9)*(x+9)$

б)$y^{2}-6y+9 = (y-3)^{2}$

в)$16x^{2} -49 = (4x-7)(4x+7)$

г)$9a^{2}+30ab+25b^{2} = (3a+5b)^{2}$

3)

a) $(n-6)^{2} - (n-2)(n+2) = n^{2} - 12n + 36 - (n^{2} -4) = n^{2} - 12n + 36 - n^{2} +4 = \\= -12n+40 = 40-12n$

б) $(3m-7n)^{2} - 9m(m-5n) = 9m^{2} - 42mn + 49n^{2} - 9m^{2} +45mn = 3mn+49n^{2} =\\ = n(3m+49n)$