(2x+y-c=2)=(x+2y-c=5)=(x-y+2c=-7) solve for x, y, and c.

I’m still confused on how to work the percentages

Atriangle has vertices of (0,3.5), (3,1.5), (0, -1.5). if it is dilated with center at the origin, and a scale factor of 2, what will be the coordinates of the image?

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