Help , algebra 1-2 ?? 5z^6-1.5z^7+z

What is the value of x in the this question ?

Which of the following would be a reasonable estimate for the weight of a pencil? a. 1 × 10^-20 lb b. 1 × 10^20 lb c. 1 × 10^2 lb d. 1 × 10^-2 lb

Which problem would you use the following proportion to solve for? 24/x = 40/100 a. what is 40% of 24? b. what percent is 24 of 40? c. twenty-four is 40% of what number? d. forty percent of 24 is what number?