8! it's timed, i promise it's simple 11. which of the following expressions is true? a. 4^3• 4^4 = 412 b. 5^2 • 5^3 > 5^5 c. 3^2 • 35 < 3^8 d. 5^2 • 54 = 58 12. which of the following expressions is true? a.8^3 • 8^2 < 8^4 b. 4^4 • 4^4 = 4^16 c. 2^2 • 2^6 < 2^8 d. 3^3 • 3^3 > 3^5 write the value of the expression. 13. 3^4/3^4 a. 3 b. 0 c. 1 d. 4 14. 4^7/4^9 a. –16 b. 1/16 c. 1/8 d. 8 multiply. write the result in scientific notation. 15. (2.3 • 10^1)(7 • 10^6) a. 1.61 • 10^7 b. 1.61 • 10^8 c. 9.3 • 10^6 d. 9.3 • 10^7 16. (1.7 ∙ 10–4)(5 ∙ 10–5) a. 8.5 ∙ 10^–9 b. 8.5 ∙ 10^20 c. 6.7 ∙ 10^–9 d. 6.7 ∙ 10^20 simplify the expression. 17. 7t4 ∙ 7t4 a. 49t^8 b. 14t^4 c. 49t^16 d14t^8 simplify the expression. 18. –x(7x – 8) a. 6x^2 – 9x b. –7x – 8x c. –7x^2 + 8x d. 7x + 8x simplify the expression. 19. 4k2(–3k2 – 4k + 5) a. –12k^4 – 16k^3 + 20k^2 b. 12k^4 – 16k^3 + 9k^2 c. –12k^3 + 20k d. k4 + 9k^2 simplify the expression. 20. (2k + 1) (k – 4) a. 2k^2 – 7k + 4 b. 2k^2 –3k + 4 c. 2k^2 + 9k + 4 d. 2k^2– 7k – 4