а)
х<span>²-4х<span>²+3=0</span></span>
<span><span>-3х<span>²+3=0</span></span></span>
<span><span><span>-3(х<span>²-1)=0</span></span></span></span>
<span><span><span><span><span>х²-1=0</span></span></span></span></span>
<span><span><span><span><span>(х-1)(х+)=0</span></span></span></span></span>
|х-1=0 = > х=1
|х+1=0 х=-1
Ответ:- 1;1
б)х<span>²+9х=0</span>
<span>х(х+9)=0</span>
<span>|х=0</span>
<span>|х=9</span>
<span>Ответ: 0;9</span>
в) <span>7х²-х-8=0</span>
D=1+224=225=15<span>²</span>
х=(15+1)/14=16/14=8/7
х=(-15+1)/14=-14/14=-1
Ответ:-1;8/7
г) 2х²-50=0
<span><span>х²-25=0</span></span>
(х-5)(х+5)=0
|х=5
|х=-5
Ответ:-5:5
1/x-x+y/xy=1/1х-1/1х+у/ху=у/ху=х
135 литров
225=100%
х =60%
225*60/100=135 литров
ответ:135 л