Anyone? please help with work

How to determine whether two known pairs of points are on the same line.

Moira has a canvas that is 8 inches by 10 inches. she wants to paint a line diagonally from the top left corner to the bottom right corner. approximately how long will the diagonal line be?

John used linear combination to solve the system of equations shown. he did so by multiplying the first equation by -3 and the second equation by another number to eliminate the x-terms. what number did jonas multiply the second equation by? 4x-6y=23x+5y=11