PQ = x - 5, QR = 2x -1, and PR = 21. Find X

A. find the power of the test, when the null hypothesis assumes a population mean of mu = 450, with a population standard deviation of 156, the sample size is 5 and the true mean is 638.47 with confidence intervals of 95 b. find the power of the test, when the null hypothesis assumes a population mean of mu = 644, with a population standard deviation of 174, the sample size is 3 and the true mean is 744.04 with confidence intervals of 95% c. find the power of the test, when the null hypothesis assumes a population mean of mu = 510, with a population standard deviation of 126, the sample size is 10 and the true mean is 529.44 with confidence intervals of 95

One x-intercept for a parabola is at the point (-0.33,0). use the quadratic formula to find the other x-intercept for the parabola defined by the equation y=-3x^2+5x+2

David pays a 20% income tax on his $2,100 salary. how many dollars is the tax? show work