A line passes through the points $A,$ $B,$ and $C.$ Find $y.$
A = (0,0), B = (3,4), C = (7,y)
Slope between AB = Slope between AC
AB slope = [ 4 - 0 ] / [ 3 - 0 ] = 4/3
AC slope = [ y - 0 ] / [ 7 - 0 ] = 4/3
y / [ 7 ] = 4/3
y = 7 (4/3)
y = 28/3