Witch operation flips the graph of a function over the x axis

Which value is not a solution of 8x^3 – 1 = 0

Acar travels at an average speed of 52 miles per hour. how long does it take to travel 299 miles

Lance lived in portugal and brazil for a total of 14 months to learn portuguese. he learned an average of 130 new words per month when he lived in portugal, and an average of 150 new words per month when he lived in brazil. in total he learned 1920 new words. write a system of equations to represent the situation. use x to represent portugal, and y to represent brazil