For #36, why is the answer 4? plz explain.

I am getting 7 as the value of b. I do not believe 4 is a correct answer!

Here's why:

General equation of a circle in the xy plane

with being the x,y coordinates of the center.

The center point can be determined from the two endpoints of the diameter because the line segment is horizontal, so we just find the center of the x coordinates of the two points:

and the radius r = diameter/2 = 8-(-2)/2 = 5

so we have

Given a point on the circle (0,b) with b>0:

options a,b,c are the right answer.

step-by-step explanation:

a linear parent function is always represented as y = x

if we write this function in the form of y=mx+c

⇒

or  

now if we plot a graph we will find these characteristics:

1) y intercept of the graph is zero so its a straight line passing through origin.

2) as we can see in both the forms of function written, values of x and y may be either positive or negative for the positive slope means points on the graph are either in first quadrant or in third one.

3) it's slope is one.