not sure how the first two pictures apply here, since they're just a single circle.
check the picture below.
the one on the left can have 3 common tangent lines, the one on the right, only two common ones.
Answer:
1) The gradient of a line perpendicular to AB.→ [-2}
2) The equation of the line perpendicular to AB and passing
through the midpoint of AB. →[y=-2x+6]

hope it helps....
have a great day!!
Answer is a because a^-2 will be changed to 1/a^2
Hope that helps
Answer:
First one, Second one, and fourth one
Step-by-step explanation: