Answer: x² + y² - a²(mx+c)²/c² = 0.
- A x² + y² - a²(mx+c)²/c² = 0
- B x² + y² = a², the original circle equation alone
- C (mx+c)² = a², the line equation squared alone
- D y = mx, leaving out the constant term c altogether
Correct answer: A. x² + y² - a²(mx+c)²/c² = 0
Explanation: Homogenize: x² + y² = a²[(y-mx)/c]² = a²(y-mx)²/c². Rearranging: x²+y² - a²(mx-y)²/c² = 0... The standard result after homogenization.
The slope of a line is the ratio of vertical change (rise) to horizontal change (run) between any two points on it - equivalently, the tangent of the angle θ the line makes with the positive x-axis.