![\left \{ {{ \frac{x}{5}*30+ \frac{y}{6}*30=- \frac{9}{10}*30 } \atop { \frac{x}{8}*56- \frac{y}{7} *56=- \frac{73}{56} *56}} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7B+%5Cfrac%7Bx%7D%7B5%7D%2A30%2B+%5Cfrac%7By%7D%7B6%7D%2A30%3D-+%5Cfrac%7B9%7D%7B10%7D%2A30+++%7D+%5Catop+%7B+%5Cfrac%7Bx%7D%7B8%7D%2A56-+%5Cfrac%7By%7D%7B7%7D++%2A56%3D-+%5Cfrac%7B73%7D%7B56%7D+%2A56%7D%7D+%5Cright.+)
![\left \{ {{6x+5y=-27} \atop {7x-8y=-73}} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7B6x%2B5y%3D-27%7D+%5Catop+%7B7x-8y%3D-73%7D%7D+%5Cright.+)
Умножим первое уравнение на 8, а второе на 5, получим:
![+\left \{ {{48x + 40y = - 216} \atop {35x - 40y = -365}} \right.](https://tex.z-dn.net/?f=+%2B%5Cleft+%5C%7B+%7B%7B48x+%2B+40y+%3D+-+216%7D+%5Catop+%7B35x+-+40y+%3D+-365%7D%7D+%5Cright.+)
________________
83x = - 581
x = - 7
6 * 7 + 5y = - 27
42 + 5y = - 27
5y = - 27 - 42
5y = - 69
y = - 13,8
Ответ : (7 ; - 13,8)
2sinx(cosx+sinx)=(cosx-sinx)(cosx+sinx)
cosx=-sinx tgx=-1 x=-П/4+Пn
2sinx=cosx-sinx
3sinx=cosx
tgx=1/3
x=arctg(1/3)+Пn
3sinx+cosx=1
6sinx/2*cosx/2=2sin^2(x/2)
sinx/2=0
x=2Пn
3cosx/2=sinx/2
tgx/2=3
x=2arctg(3)+2Пn
Y=0, y=-2/3 (минус две третьих)
<span>а) (3х²)³ = 9х<u>6ст</u></span>
<span><span>в) (-2а4степ. b²)³=-8а<u><em>12ст</em></u>б<u>6ст</u></span></span>
<span><span><span>д) (-а²bc³ )5степ.=-а<u>10ст </u>б<u>5ст </u>с<u>15ст</u></span></span></span>
<span><span><span><u>
</u><u /><span> б) (4m)²=16m<u>2ст</u></span></span></span></span>
<span><span><span><span> г) (-3x²y) 4степ=81х<u>8ст</u>у<u>4ст</u></span></span></span></span>
<span><span><span><span><u>
</u><span> е) (-a³b²c)² 484.=-а<u>ст1452</u> б<u>ст968</u> с<u>ст968</u></span></span></span></span></span>