\(\frac{3a^3\left(x^2-1\right)^4}{3a^3\left(x^2-1\right)^3}=15\)
\(x^2-1=15\)
\(x^2=15+1\)
\(x^2=16\)
\(x^2=\left(\pm4\right)^2\)
\(x=\pm4\)
\(\frac{3x^5-4x^3}{x^3}-\frac{\left(3x+1\right)^3}{3x+1}-\frac{3x^7}{x^5}=0\)
\(\frac{x^3\left(3x^2-4\right)}{x^3}-\left(3x+1\right)^2-3x^2=0\)
\(3x^2-4-\left(3x+1\right)^2-3x^2=0\)
\(-4-\left(3x+1\right)^2=0\)
Không tìm được x thoả mãn yêu cầu vì \(-4-\left(3x+1\right)^2\le-4< 0\)
\(\frac{x^2+\frac{1}{2}x}{\frac{1}{2}x}-\frac{\left(2x+1\right)^3}{\left(2x+1\right)^2}+\frac{\left(x+1\right)^5}{\left(x+1\right)^2}=0\)
\(\frac{\frac{1}{2}x\left(2x+1\right)}{\frac{1}{2}x}-\left(2x+1\right)+\left(x+1\right)^3=0\)
\(\left(2x+1\right)-\left(2x+1\right)+\left(x+1\right)^3=0\)
\(x+1=0\)
\(x=-1\)
