y=mx+b is the equation of a line;
m=slope , b= y-intercept
m= -3/2 ; so we have : y= (-3/2)x+b
We are give a set of points which it passes through, we can simply plug them in:
1 = (-3/2)(4)+b (4 is the x and 1 is the y)
We get 1 = -6 +b .... 7=b
our final equation is : y=(-3/2)x+7