11the 'little rearrangement' was the difficult part.
4 Answers
1given, f(x)=\frac{2x^4-14x^2-8x+49}{x^4-7x^2-4x+23} \\ \\ by\ doing\ a\ little\ re-arrangement,\ we\can\ show\ that\ \\ \\ f(x) = 2+\frac{3}{(x^2-4)^2+(x-2)^2+3}\\ \\ now (x^2-4)^2+(x-2)^2+3}>3\\ \\ which\ takes\ its\ minimum\ at\ x=2 \\ so\ range\ will\ be\ f(x)\varepsilon \ (2,3]