Intersections of Circles/Lines

A circle has center (7, −3) and is tangent to the x-axis. What is the equation of the circle in standard form?

Which equation represents a circle with diameter 8 that is tangent to the horizontal line y = 2?

• (−1, −3) only

• (−3, −7) and (−1, −3)

• (−3, −7) only

• (−3, −7) and (−1, −5)

• Two points in quadrant I and II

• No real intersection points

• One point tangent in quadrant IV

• Two points in quadrant I and IV

What is the radius of a circle tangent to the x-axis with center at (a, b) where b > 0?

• Radius equals sqrt(a^2 + b^2)

• Radius equals a + b

• Radius equals |b|

• Radius equals |a|

A circle is tangent to both axes and has its center in quadrant I. Which standard-form equation could be its equation?

• {(−1, 1), (0, −1)}

• {(−1, −3), (2, 3)}

• {(−2, −5), (1, 1)}

• {(0, −1), (−1, −3)}

• {(0, −1), (1, 1)}

• Exactly three solutions

• Zero solutions

• Exactly two solutions

• Infinitely many solutions

• Exactly one solution

• −2/9

• −9/2

• 1/2

• 2/9

• 9/2

• y − 7/2 = (−7/5)(x − 5/2)

• y − 7/2 = (7/5)(x − 5/2)

• y − 7/2 = (5/7)(x − 5/2)

• y = (7/5)x − 1/2

• y − 7/2 = (−5/7)(x − 5/2)