The equations x minus 2 y = 4, 4 x + 5 y = 8, 6 x minus 5 y = 15, and x + 2 y = 0 are shown on the graph below. On a coordinate plane, there are 4 lines. Green line goes through (0, 0) and (2, -1). Blue line goes through (0, negative 2) and (2, negative 1). Pink line goes through (0.75, negative 2), and (2.5, 0). Purple line goes through (0, 1.5) and (2, 0).

Which system of equations has a solution of approximately (1.8, –0.9)?
6 x minus 5 y = 15 and x + 2 y = 0
4 x + 5 y = 8 and 6 x minus 5 y = 15
x minus 2 y = 4 and 4 x + 5 y = 8
6 x minus 5 y = 15 and x minus 2 y = 4

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