Х+81х⁻¹=18|*x
х²+81=18x
(x+9)²=0
x+9=0
x=-9
6-6cos^2x - 5 cosx + 5 = 0
6-6t^2 -5t+5=0
D=25+264=289
t1=(-5+17)/12=1
t2=(-5-17)/12 - не подходит так как < -1
Cosx=1
Ответ X=0+2пn, n принадлежит z
<em>Ответ:</em>
<em>x1 = -1; x2 = 0.8</em>
<em>Объяснение:</em>
<em>5х² = х + 4</em>
<em>5x² - x - 4 = 0</em>
<em>D = 1² - 4•5•(-4)</em>
<em>D = 1 + 80</em>
<em>D = 81</em>
<em>x1 = (-1 - √81)/(2 • 5) = -10/10 = -1</em>
<em>x2 = (-1 + √81)/(2 • 5) = 8/10 = 0.8</em>
<em>Удачи)))</em>
(2/7 - 3/4)·(2/13 - 1/2) = 117/728
1) 2/7 - 3/4 = 8/28 - 21/28 = -13/28
2) 2/13 - 1/2 = 4/26 - 13/26 = -9/26
3) -13/28·(-9/26) = 9·13/28·26 = 117/728
Расскрываем скобки 6,2a-3+<span>4-7,2a
6,2а-7.2а+(-3)+4
-1а+1</span>