8х + 16 = 0,

8х = -16,

х = -16 : 8,

х = -2,

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3х - 21 ≤ 0,

3х ≤ 21,

х ≤ 7,

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8х² - 12х + 1 = 0,

Д = (-12)² - 4*8*1 = 144 - 32 = 112,

х1 = (12 + 4√7) / 2*8 = (3 + √7)/4,

х2 = (12 - 4√7) / 2*8 = (3 - √7)/4,

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(3,05 - 2,125 * 3,2) : 5/6 + 1 1/6 =

= (3,05 - 6,8) * 6/5 + 1 1/6 =

= -3,75 * 6/5 + 1 1/6 =

= -375/100 * 6/5 + 1 1/6 =

= -9/2  + 7/6 = -27/6 + 7/6 = -20/6 = -3 1/3,

(а²+10а+25)/(а²-25) =

= (а+5)²/(а-5)(а+5) = (а + 5)/(а - 5),

(в + 5)² = в² + 10в + 25,

36ву - 9су = 9у * (4в - с),

(64в⁻⁶)⁻¹⁾⁶ = 64⁻⁶°⁽⁻¹⁾⁶⁾ = 64¹ = 64