1 1/4 - (1/15 + 1/10 + х) = 3/4
5/4 - (2/30 + 3/30 + х) = 3/4
- (5/30 + х) = 3/4 - 5/4
- (5/30 + х) = - 2/4
5/30 + х = 2/4
1/6 + х = 1/2
х = 1/2 - 1/6
х = 3/6 - 1/6
х = 2/6
х = 1/3
<u>проверка:</u>
1 1/4 - (1/15 + 1/10 + 1/3) = 3/4
5/4 - (2/30 + 3/30 + 10/30) = 3/4
5/4 - 15/30 = 3/4
5/4 - 1/2 = 3/4
5/4 - 2/4 = 3/4
3/4 = 3/4
Переписывать не буду сам пример
=х(х²-1)-(х³-2х²+2х²-4х+4х-8)=х³-х-х³+8=8-х
10+16=26
26-22=4
Ответ:4 человека
[cos105⁰(cos277⁰sin172⁰-cos7⁰sin82⁰]/(2√2)⁻²=
=(2√2)²·cos105⁰·[1/2(sin(172⁰-277⁰)+sin(172⁰+277⁰))-1/2(sin(82⁰-7⁰)+sin(82⁰+7⁰))]=
=4·2·1/2·cos105⁰·(sin(-105⁰)+sin449⁰-sin75⁰-sin89⁰)=
=4·cos105⁰·(-sin105⁰+sin(2π+89⁰)-sin75⁰-sin89⁰)=
=-4·cos105⁰·sin105⁰-4·cos105⁰·sin75⁰=
=-2·sin210⁰-4·1/2·(sin(75⁰-105⁰)+sin(75⁰+105⁰)=
=-2sin(π+30⁰)-2[(sin(-30⁰)+sin180⁰)]=
=-2(-sin30⁰)-2[(-sin30⁰)+0]=2sin30⁰+2sin30⁰=4sin30⁰=4·(1/2)=2