SOLUTION: In 10–12, write an equation of each circle that has the given point as center and the given value of r as the length of the radius. 10. (0,0),r=7 11. (2,-5),r=4 12. (-3,8),r=11

Algebra ->  Circles -> SOLUTION: In 10–12, write an equation of each circle that has the given point as center and the given value of r as the length of the radius. 10. (0,0),r=7 11. (2,-5),r=4 12. (-3,8),r=11       Log On


   

Question 880122: In 10–12, write an equation of each circle that has the given point as center and the given value of r as the length of the radius.
10. (0,0),r=7
11. (2,-5),r=4
12. (-3,8),r=11
13. a. Find the coordinates of the points(s) of intersection of the circle x2+y2=25 and the line y+5=2x.
b. Is the line a secant or a tangent of the circle?
Answer by josgarithmetic(39625) About Me  (Show Source):
You can put this solution on YOUR website!
Numbers 10, 11, and 12 can be answered with filling the information into the standard form equation of a circle. %28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2 has center (h,k) and radius r.

Number 13, use substitution.
y=2x-5.
x%5E2%2B%282x-5%29%5E2=25
x%5E2%2B4x%5E2-10x%2B25=25
5x%5E2-10x=0
x%5E2-2x=0
x%28x-2%29=0
x=0 or x=2.
Correspondingly y=2%2A0-5=-5 or y=2%2A2-5=-1.
These points of intersection are (0,-5) and (2,-1). The line through these two points of the circle is a secant.