<span>7x</span>²<span> + 6x + 1 = 0</span>
D = 6²<span> - 4·7·1 = 8</span>
<span><span><span>x1 = (</span><span>-6 - √8)/2*7</span> = <span><span>-3/</span>7</span> - <span>17</span><span>√2</span> ≈ -0.63060
</span></span><span><span>x2 = (</span><span>-6 + √8)/2*7</span> = <span><span>-3/</span>7</span> + <span>17</span><span>√2</span> </span>≈ -0.22654<span>
</span>
2. 3sinx(2cosx+1) -2(2cox+1)=0
(2cox+1)(3sinx-2)=0
cosx=-1/2 sinx=2/3
x=+-(pi/3)+2pi*n x= (-1)^n* arcsin2/3 +pi*n
Приводим все дроби к общему знаменателю
1)6z-24=z-69 z=-9
2)4x+28=x+1 3x=-27 x=-9
3)7y-168=y-186 y=3 в 4) плохо видны знаки решается аналогично