Suppose y varies directly with x. If y = -4 when x = 8, what is the equation of direct variation?
Complete the steps to write the equation of direct variation.
1. Start with the equation of direct variation y = kx.
2. Substitute in the given values for x and y to get
3. Solve for k to get
4. Write the direct variation equation with the value found for k. The equation is

Anew test for ra is being developed. the test is administered to 750 patients with ra and 750 without ra. for the sake of the question, assume the prevalence of ra in this population is 50%. of the 750 patients with ra, 575 have a positive result. of the 750 patients without ra, 150 have a positive result. what is the positive predictive value of the new test? a575/(575+150) b. 600/(600+ 150) c. 575/(575+125) d. 600/(600+ 125)