+0  
 
0
32
1
avatar

Let C be the circle with equation x^2+2y-9=-y^2+28x+19. If (a,b) is the center of C and r is its radius, what is the value of a+b+r?

 Oct 1, 2021
 #1
avatar+35057 
+2

Put everything except the constants on one side

 

x^2 -28x     + y^2 +2y = 28    complete the squares for x and y

(x-14)^2      + (y+1)^2   = 28 + 196 + 1 =225

 

center is   14,-1       radius is sqrt225 = 15   <=========you can finish

 Oct 1, 2021

18 Online Users

avatar