
Victoria V. answered 07/16/20
20+ years teaching Algebra 2 subjects & beyond.
Because this is a polynomial (if you multipied it all out, all of the exponents would be positive integers), and these are "nice" graphs - smooth curves, no quick changes, no x's without y-values... so their x's start at negative infinity and go to positive infinity. This is a DOMAIN of ALL REAL NUMBERS or in interval notation it is (-∞, +∞)
Again, if you multiplied all of these terms together, the leading term (the one with the biggest exponent) would have an exponent of 5 (x5) which makes it an ODD polynomial. All odd polynomials have y-values from neg infinity to pos infinity, so it has a RANGE of ALL REAL NUMBERS or in interval notation it has a range of (-∞, +∞)