11. Simplify this expression 75 x 7" 12. What is the simplified form of the expression? (5xy)(3xy) 13. What is the simplified form of the expression? (9 10)(8 10) 14. What is the simplified form of the expression? (6 x 10-)(8 x 10) 15. Astronomers measure large distances in light-years. One light-year is the distance that light can travel in one year, or approximately 5.88 x 102 miles. Suppose a star is 6.3 x 10 light years from Earth. In scientific notation, approximately how many miles is it? 16. A dinosaur fossil is 128, 320,000 years old. How can you express this age in scientific notation with the highest level of precision. 17. Electromagnetic waves travel at a rate of 3 x 10 meters per second. How many seconds would it take for an electromagnetic wave to travel from a satellite to the surface of the Earth if the satellite is orbiting at a height of 2.9 x 10 meters? (Hint: Time is distance divided by rate) 18. Simplify the following. (gs)" 19. Simplify the following. x(x-3)* 20. Simplify the following (4b)(be")-3 21. Simplify the following 3g*(2gh) 11. Simplify this expression 75 x 7" 12. What is the simplified form of the expression? (5xy)(3xy) 13. What is the simplified form of the expression? (9 10)(8 10) 14. What is the simplified form of the expression? (6 x 10-)(8 x 10) 15. Astronomers measure large distances in light-years. One light-year is the distance that light can travel in one year, or approximately 5.88 x 102 miles. Suppose a star is 6.3 x 10 light years from Earth. In scientific notation, approximately how many miles is it? 16. A dinosaur fossil is 128, 320,000 years old. How can you express this age in scientific notation with the highest level of precision. 17. Electromagnetic waves travel at a rate of 3 x 10 meters per second. How many seconds would it take for an electromagnetic wave to travel from a satellite to the surface of the Earth if the satellite is orbiting at a height of 2.9 x 10 meters? (Hint: Time is distance divided by rate) 18. Simplify the following. (gs)" 19. Simplify the following. x(x-3)* 20. Simplify the following (4b)(be")-3 21. Simplify the following 3g*(2gh)