Question

The equations of the tangents to the circle $x ^ { 2 } + y ^ { 2 } = 50$at the points where the line $x + 7 = 0$ meets it, are.

• A. $7 x \pm y + 50 = 0$
• B. $7 x \pm y - 5 = 0$
• C. $y \pm 7 x + 5 = 0$
• D. $y \pm 7 x - 5 = 0$

Answer 1

Answer: (A)

$7 x \pm y + 50 = 0$

Answer 2

Points where $x + 7 = 0$ meets the circle $x ^ { 2 } + y ^ { 2 } = 50$ are $( - 7,1 )$ and $( - 7 , - 1 )$. Hence equations of tangents at these points are $- 7 x \pm y = 50$ or $7 x \pm y + 50 = 0$.