Final answer:
The equation 20x = -5y + 8 already contains only positive exponents. Negative exponents denote the reciprocal of the base raised to the positive exponent, but this rule isn't required to rewrite the given equation.
Step-by-step explanation:
The equation 20x = -5y + 8 needs to be rewritten with only positive exponents. We do not need to change anything about the equation itself because it already contains only positive exponents. However, it's important to understand how negative exponents work in case they appear in an equation. According to the rule of exponents, a negative exponent indicates that the base should be taken as the reciprocal. For example, x-n is the same as 1/xn, where n is a positive integer. Now, back to the original equation, if we want to isolate 'y', we can rewrite the equation as y = -4x + 1.6. No negative exponents are present or necessary in this form.