What is the value of
? 2/15 ÷ 5/12

Which equation represents the line that passes through the points and (4, 10) and (2, 7)? y = 3/2x - 11y = 3/2x +4y = - 3/2x + 19y = - 3/2x + 16

Suppose that the price p (in dollars) and the weekly sales x (in thousands of units) of a certain commodity satisfy the demand equation 4p cubedplusx squaredequals38 comma 400. determine the rate at which sales are changing at a time when xequals80, pequals20, and the price is falling at the rate of $.20 per week.

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?