21 : 53 = 220 : (y + 300)
y + 300 = 53 * 220 : 21
y + 300 = (555)5/21
y = (555)5/21 - 300
y = (255)5/21
5) 29 : 30 = 78 : (3y - 2)
3y - 2 = 78 * 30 : 29
3y - 2 = (80) 20/29
3y = (82) 20/29
y = (27)49 /87
<span>х²+6х+8=0
По теореме обратной теореме Виетта:
x=-4
x=-2</span>
<span>√121-10√6,4•√0,1=
11-10</span>√(6.4*0.1)=
11-10√0.64=
11-√(0.64*100)=
11-√64=
11-8=3
1)1/(n-1)(n-2) + 1/n(n-1)=(n+n-2)/n(n-1)(n-2)=(2n-2)/n(n-1)(n-2)=2(n-1)/n(n-1)(n-2)=
=2/n(n-2)
2)2/n(n-2) : (n+2)/n(n-2)=2/n(n-2) *n(n-2)/(n+2)=2/(n+2)