1) 19/8 + 11/12 = 2 3/8 + 11/12 = 2 9/24 + 22/24 = 2 31/24 = 3 7/24
2) 3 7/24 : 5/48 = 79/24 : 5/48 = 158/5 = 31,6
Ответ 31,6
8-8-8-8-8-8-8--8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8=0
15%=0,15
0,15 * 620=93 (га) - убрали за сутки
Ответ: 93 га
пусть х^2 будет t, тогда х^4 будет t^2.
t^2 - 13t + 36 = 0
D = b^{2} - 4ac
D= 169 - 4*1*36 = 169 - 144 = 25 = 5^{2}
t1,2= -b+- корень из D /{2a
t1 =(13+5)/2} = 9
t2 = (13-5)/2 = 4
(3-x)²-(x+4)²=7
9-6x+x²-(x²+8x+16)=7
x²-6x+9-x²-8x-16=7
-6x-8x=7+16-9
-14x=14
x=-1