Final answer:
After applying exponent rules, only options b ((8^3)(8^9) = 8^12) and c (5^2 = 1/5^-2) are true. Options a, d, and e are false because they misrepresent either the concept of degrees or the rules of exponents.
Step-by-step explanation:
Let's examine each of the given expressions to determine which equations are true. In mathematics, especially in algebra, understanding exponent rules is crucial when working with power expressions.
- a. 15° is an angle measure and cannot be equal to the number 1.
- b. (8^3)(8^9) = 83+9 = 812 based on the property of exponents that states when multiplying powers with the same base, we add the exponents.
- c. 5^2 = 25 and 1/5^-2 also equals 25 because the negative exponent indicates reciprocal. Hence, this equation is true.
- d. (6^5)3= 65*3 = 615, not 68. Therefore, this equation is not true.
- e. 3^7/3^9 = 37-9 = 3-2, not 316. This equation is also not true.
From our analysis, options b and c are the only true equations.