For what values of m does the graph of y=mx2-58-2 have no x-intercepts?

Which representation has a constant of variation of -2.5

Ineed i been stuck on this question since yesterday

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.