28 - 100\%
х - 75\%
х=28*75/100 = 21 ученик занимается спортом
Ответ: 21 ученик
787/25 = 31 48/25 = 32 23/25
144/17 = 8 8/17
1000/33 = 30 10/33
1
а)3/y²
б)7a/2c
в)(2a-1)(2a+1)/(a-3)(a+3) *(a+3)/3(2a+1)=(2a-1)/(3(a-3)
г)p/(p-q)+p/q=(pq+p²-pq)/q(p-q)=p²/a(p-q)
(p-q)/p* p²/q(p-q)=p/q
2
14+18z-12-5z-3-13z-1=13*2/3-1=26/3-1=(26-3)/3=23/3=7 2/3
1
а)2ax/3
б)b/2a
в)5(x+2)/(x-1) *(x-1)(x+1)/(x-2)(x+2)=5(x+1)/(x-2)
г)c/y-c/(y+c)=(cy+c²-cy)/y(y+c)=c²/y(y+c)
(y+c)/c * c²/y(y+c)=c/y
2
66-14y-6-3y-9=56-17y=56-17*4/7=56-68/7=(372-68)/7=304/7=43 3/7
<span>10у-6х=30
-6х = 30 -10у
6х = 10у - 30
х = (10у -30)/6
х = 2( 5у -15)/6
х = (5у-15)/3
</span>