[tex]f(x)=7 x^{5} -5 x^{4} +2[/tex] is a polynomial function, and every polynomial function is continuous everywhere; therefore, [tex]f(x)[/tex] is continuous from minus infinite to infinite.
In interval notation: (-∞,∞)
Remember that in interval notation you use brackets [ ] to indicate that the end points are included, and parentheses to indicate that the end points are excluded; since infinite is not a defined point, it cannot be included, so we use parentheses.
