Answer is C
Y-y1=m(x-x1)
y1=-1/2 x=4/5, m=3/4
Hey there!
The answer is 
We will start by forming an equation to solve this.
So we are starting with a number,
, then doubling it and adding
, which gives us 25.
So:

Now we solve this equation:



Have a super awesome day!
So, these are actually pretty simple once you learn the equality used to solve for "x" and when to implement this method. You can use this equality to solve for a segment "x" anytime that two secant lines cutting through a circle come from the same point outside the circle.
Secant: by geometric definition is just a straight line that cuts a curve into multiple pieces.
I did one of them for you hopefully you can use my work for "a" to help you solve for "b".
For a. I got x=7.
Answer:
√61 ≈ 7.81
Step-by-step explanation:
Distance formula:
√(x₂ - x₁)² + (y₂ - y₁)²
√(2 - (-4))² + (5 - 0)²
√(2 + 4)² + 5²
√6² + 5²
√36 + 25
√61