Log₂² x² - 15log₂x - 4≤0

[latex]4 log_{2} ^{2} x - 15 log_{2}x - 4 leq 0 [/latex][latex] log_{2} x = t[/latex]4t² - 15t - 4 ≤ 0D = 225 + 64 = 289t = (15 + 17)/8 = 4    или    t = (15 - 17)/8 = - 1/4см. рис.t ≥ - 1/4   это системаt ≤ 4[latex] left { {{log_{2} x geq - frac{1}{4}} atop {log_{2} x leq 4}} ight. [/latex]x ≥ 2 ^ (-1/4)x ≤ 2^4[latex] left { {{x geq frac{1}{ sqrt[4]{2} } } atop {x leq 64}} ight. [/latex]