11. Which of the following expressions is true?

A. 4^3 * 4^4 = 4^12
B. 5^2 * 5^3 > 5^5
C. 3^2 * 3^5 > 3^10
D. 5^2 * 5^4 < 5^8

B. 5^2 * 5^3 > 5^5

12. Which of the following expressions true?

A. 2^4 * 2^3 = 2^12
B. 3^3 * 3^6 > 3^8
C. 4^2 * 4^2 > 4^4
D. 5^5 * 5^2 = 5^10

A. 2^4 * 2^3 = 2^12

To determine which of the given expressions is true, let's simplify each expression step-by-step:

A. 4^3 * 4^4 = 4^(3+4) = 4^7

B. 5^2 * 5^3 = 5^(2+3) = 5^5

C. 3^2 * 3^5 = 3^(2+5) = 3^7

D. 5^2 * 5^4 = 5^(2+4) = 5^6

Now let's compare the simplified expressions:

A. 4^7
B. 5^5
C. 3^7
D. 5^6

By comparing the powers, we can see that:

4^7 is not equal to 4^12 (option A is false)
5^5 is greater than 5^6 (option B is false)
3^7 is greater than 3^10 (option C is false)
5^6 is less than 5^8 (option D is true)

Therefore, the correct expression is option D. 5^2 * 5^4 < 5^8.