X4 + 2x²<span> - 8 = 0
</span><span> замена </span>y<span> = </span>x2
y² + 2y<span> - 8 = 0
</span>D = b2 - 4ac = 22<span> - 4·1·(-8) = 4 + 32 = 36
</span>y1 = -2 - √36
----------- =-4
2*1
<span><span><span>y2 = </span><span>-2 + √36</span> </span><span>
--------------- =2
2*1
</span></span><span><span>x</span></span>²<span><span> = </span>-4</span>
<span><span>x</span></span>²<span><span> = </span><span>2
х1=</span></span>√2
х2=-√2
120с = 2 минутам
3ч = 180минут
4 минутах= 240с
5минутах 30 с =330 с
7,8-(-5,2+3,4)=7,8+5,2-3,4=9,6