4.
a) ab - 4b + 7a - 28 = b(a - 4) + 7(a - 4) = (b + 7)(a - 4)
b) x^3 - 5x^2 + x - 5 = x^2(x - 5) + 1(x - 5) =(x^2 + 1)(x - 5)
5.
x, x+1, x+2
(x+1)(x+2) - x^2 = 50
x^2 + 2x + x + 2 - x^2 = 50
3x + 2 = 50
3x = 48
x = 16
x + 1 = 17
x + 2 = 18
Ответ: 16, 17, 18
3х - 1/6 -2х+3/8 = 2 |*24
72x - 4 -48x + 9 = 2
24x = 2-9+4
24x = -3
x= -1/8
2a*(a-b)/(a-b)(a+b)=2a/a+b
<span>7х(в квадрате)-14х=0</span>
<span>7х*(х-2)</span>
<span>7х=0 или х-7=0</span>
<span>х=0 и х=2</span>
<span>ответ 0 и 2</span>