Let's first try the coordinates (2,1). 4x - 7 should be equal to 1 by replacing x by 2
4x - 7 = 42 - 7 = 8 - 7 = 1
So 4x - 7 = y = 1 when x = 2
Let's replace by the coordinates (4,9). 4x - 7 should be equal to 9 when x = 4.
4x - 7 = 44 - 7 = 16 - 7 = 9
So 4x - 7 = y = 9 when x = 4
Both coordinates verifies the equation, so both ordered pairs are solution of the equation.
I've added a picture of the graph of the equation with 2 points of both coordinates.
Hope this Helps! :)
