Question

Срочно нужны ответы зарание спасибо

Answer 1

Ответы:

$1) \frac{90}{(3\sqrt{5})^2} = \frac{90}{3^2 * (\sqrt{5})^2} = \frac{9*10}{9*5} = 2$

$2) \frac{\sqrt{7}*\sqrt{15}}{\sqrt{21}} = \sqrt{\frac{7*15}{21}} = \sqrt{\frac{7*5*3}{7*3}} = \sqrt{5}$

$3) x^2 - 6x - 16 = 0\\\\D = 36 + 64 = 100\\\\\sqrt{D} = 10\\\\x_1 = \frac{6-10}{2} = \frac{-4}{2} = -2\\   \\x_2 = \frac{6+10}{2} = \frac{16}{2} = 8$

$\left \{ {{3 + 5x > 1} \atop {6 - 3x < 0}} \right. \\\\\left \{ {{5x > 1 - 3} \atop { - 3x < -6}} \right\\\\\left \{ {{5x > -2} \atop { - 3x < -6}} \right\\\\\left \{ {{x > -0,4} \atop {x > 2}} \right$

x∈ (-0,4; 2) ∪ (2; ∞)