What is the solution to the system of liner equations. y-4x=7 2y+4x=2 please help!!

What is (28 + 7 + 6 + 3) x 1/2 show your work

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

Select the margin of error that corresponds to the sample mean that corresponds to each population: a population mean of 25, a standard deviation of 2.5, and margin of error of 5%