The vertex is where two lines make a point and the answer would be letter C. A
1) use the distance formula to find that the radius (r) of the circle = 5
2) use the midpoint formula to find that the center of the circle (h,k) = (3, 0)
3) Now use the formula of a circle and input the (h,k) and r to create:
(x - 3)² + (y - 0)² = 5² → (x - 3)² + y² = 25
4) input the "x" value given in the question (x = 0) and solve for "y":
(0 - 3)² + y² = 25 → 9 + y² = 25 → y² = 16 → y = +/- 4
Since the question states that "b" must be positive, you can disregard the -4.
Answer: b = 4
5x/7 - 5 = 50 is 4. x = 77
6×7=42 so the number missing is 42
