distance formula

standard form (x-h)^2 + (y-k)^2=r^2

General form x^2+y^2+ax+by+c=0

Find Center(h,k) find radius of each circle graph its cirlces

21. 2(x-3)^2 +2y^2=8

divide all by 2

(x-3)^2 +y^2=4

Center=(3,0)

r=2

xintercepts {5,1}

31. 2x^2 +2y^2 minus 12x +8y minus 24=0

all i know is minus 24, complete the square, factor

Find standard equation

37. Center (2,3) tangent to x axis

(x-2)^2 + (y-3)^2 =9

How did they get 9?

How does tangent to x axos give me radius of 9?

41. center (-1,3) tangent to line y=2

(x+1)^2 + (y-3)^2 =2

How they get radius of 2?