Question

ку) помогите решить
$0.3(x \times 2 )0.02(x + 4) = 2.9$
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Answer 1

Ответ:

$0.3(x \times 2)0.02(x + 4) = 2.9 \\0.3 \times 2x \times 0.02(x + 4) = \frac{29}{10} \\ 0.012x (x + 4) = \frac{29}{10} \\ 0.012x {}^{2} + 0.048x = \frac{29}{10} \\ \frac{3}{250} x {}^{2} + \frac{6}{125} x - \frac{29}{10} = 0 \\ \frac{3x {}^{2} + 12x - 725 }{250} = 0$

х≠250

$3x {}^{2} + 12 x- 725 = 0 \\ a = 3 \: b = 12 \: c = - 725 \\ D = b {}^{2} - 4ac = 12 {}^{2} - 4 \times 3 \times ( - 725) = 144 + 8700 = 8844 = 2 \sqrt{2211} \\ x½ = \frac{ - b±D}{2a} = \frac{ - 12±2 \sqrt{2211} }{6} = - 2±2 \sqrt{2211}$

x=-2+2√2211 и -2-2√2211