<span>0.2(2.1х-2.3у)-0.4•(3.1к.у+1.9х)=0
0,42х-0,46у-1,24ху-</span><span>0,76х=0
-0,34х-0,46у-1,24ху=0</span>
7sin²x+7cos²x = 7 ( В формулки заглядывать надо)
7-5+2
7x+9-9=4x+3-9
7x-4x=-6
3x=-6
x=-2
Ответ:x=-2.
1.
<span>
x </span><span><span>-5
</span><span>
-4
</span><span>
-3
</span><span>
-2
</span><span>
-1
</span><span>
0
</span><span>
1
</span><span>
2
</span><span>
3
</span><span>
4
</span><span>
5
</span></span><span>
y </span><span><span><span>5,9
</span><span>
4,2
</span><span>
2,9
</span><span>
2
</span><span>
1,4 </span><span>
1
</span><span>
0,7
</span><span>
0,5
</span><span>
0,3
</span><span>
0,2
</span><span>
0,2
</span></span></span><span>
2.
y=1
3.
</span>
y=0