Describe how to simplify the expression

3^-6 / 3^-4 = 3^[-6 -(-4)] = 3^-6 + 4 = 3^-2

so answer is D last option

Keep the base the same and then subtract the exponents

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40

entering that problem on the tube might get you an answer