Question

помогите!!
$3a + \frac{1}{2a} = 4$
если так, то
$9a {}^{2} + \frac{1}{4a {}^{2} } =$
???​

Answer 1

$3a+\frac{1}{2a}=4\\\\(3a +\frac{1}{2a})^{2} =4^{2}\\\\9a^{2}+2*3a*\frac{1}{2a}+\frac{1}{4a^{2}}=16\\\\9a^{2}+3+\frac{1}{4a^{2}}=16\\\\9a^{2}+\frac{1}{4a^{2}}=16-3\\\\\boxed{9a^{2}+\frac{1}{4a^{2}}=13}$

Answer 2

Решение во вложении.

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