Question

5. Решите уравнение: |4х2 + 4x| - 1 = 0

Answer 1

$\displaystyle |4x^2+4x|-1=0\\\\\left[\begin{array}{1.2.3}4x^2+4x=1\\4x^2+4x=-1\\\end{array}\right \\\\1) 4x^2+4x+1=0\\\\(2x+1)^2=0\\\\x=-\frac{1}{2}\\\\ 2) 4x^2+4x-1=0\\\\D=16+16=32\\\\x_{1.2}=\frac{-4 \pm 4\sqrt{2}}{8}\\\\x_{1.2}=\frac{-1 \pm \sqrt{2}}{2}$

ответ: $\displaystyle -\frac{1}{2}; \frac{-1+\sqrt{2}}{2}; \frac{-1-\sqrt{2}}{2}$