Question 152388
Note that our m must be =-1/2.

So, we can form an equation with (3,-1)

y-(-1)=-1/2(x-3)
y=-1/2x+1/2

So, this is the line by which we want to find the y value at x=4.

y=-1/2(4)+1/2=-3/2


So, k must be -3/2.

{{{graph( 300, 200, -5, 5, -5, 5, (-1/2)x-9/2, (-1/2)x+1/2)}}}