What is the image of the point (2,7) after a rotation of 90∘ counterclockwise about the origin?

Given the system of equations presented here: 2x + 4y = 14 4x + y = 20 which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? multiply the second equation by â’4 to get â’16x â’ 4y = â’80 multiply the second equation by â’1 to get â’4x â’ y = â’20 multiply the first equation by 2 to get 4x + 8y = 28 multiply the first equation by â’1 to get â’2x â’ 4y = â’14

What are linear equations? could'ya explain too me, ? ! and how do you see what graph is a proportional relationship?

Hdtv screens usually have a width-to -height ratio of 16: 9. which screen dimensions are in the same proportion?