Решение
<span>х⁴-4х²-5=0
x</span>² = t > 0
t² - 4t - 5 = 0
t₁ = - 1 не удовлетворяет условию t > 0
t₂ = 5
x² = 5
x₁ = - √5
x₂ = √5
Х+8/3-х-2/5=2
5(х+8)-3(х-2)=30
5х+40-3х+6=30
2х+46=30
2х=30-46
2х=-16
х=-8
1) = 6X^2 - 2X + 5 + 10X - 5X^2 = X^2 + 8X + 5
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2) = 6XY + 8Y - 2XY - 8Y + 1 = 4XY + 1
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(х-4)²=( x-5 )( x+2 )
х²-8х+16=х²-5х+2х-10
<u>х²</u>-<u>8х</u>+<em>16</em>-<u>х²</u>+5х-2х+<em>10= 0 выделенное подчеркиваем разными чертами</em>
<em>-5х+26=0</em>
<em>-5х=-26</em>
<em>х=<em>-26: (-5)</em></em>
<em><em>х=5.2</em></em>
7(x + 1/x) - 2 (x^2 + 1/X^2) = 9
7x+7/x-2x^2-2/x^2=9
6x+7-x^2-2=9
6x+7-x^2-2-9=0
x^2-6x+=0
D=36-20=16=4^2
x1=(36-4)/2=16
x2=(36+4)/2=20
ответ: 16;20