The slope between two points #(x_1, y_1) & (x_2, y_2)# is: #m=(y_2-y_1)/(x_2-x_1)# => thus in this case the slope between #(4, 4) & (-4, -2)# is: #m=(-2-4)/(-4-4)=(-6)/(-8)=3/4#
using point slope formula: #y-y_1=m(x-x_1)#, we get: #y - 4=3/4(x-4)#, expand and simplify: #y=(3/4)x+1# => equation in slope-intercept form