[tex]\it E(x)=\dfrac{x^3+64}{7x^2-25}:\dfrac{x^2-16}{\sqrt7x+5}= \dfrac{x^3+64}{7x^2-25}\cdot\dfrac{\sqrt7+5}{x^2-16}\\ \\ \\ x^3+64=x^3+4^3=(x+4)(x^2-4x+16)\\ \\ x^2-16=x^2-4^2=(x-4)(x+4)\\ \\ 7x^2-25=(\sqrt7)^2x^2-5^2=(\sqrt7x-5)(\sqrt7x+5)\\ \\ Expresia\ devine:[/tex]
[tex]\it E(x)=\dfrac{(x+4)(x^2-4x+16)}{(\sqrt7x-5)(\sqrt7x+5)}\cdot\dfrac{\sqrt7x+5}{(x-4)(x+4)} =\dfrac{x^2-4x+16}{(\sqrt7x-5)(x-4)}[/tex]
