start with this equation. y=kx+a
then fill it in with k being your coefficient. you will not be able to get a yet. it should look like this.
5=(1/2)(4)+a
5=2+a
now solve
5-2=a
a=3
now to finish this off you need to make the equation which will be in the same format but without the x and y filled in.
y=(1/2)x+3
