What is the radius of the circle defined by x2 + 2x + y2 + 6y − 39 = 0? 49 9 7 81

radius = 7

the equation of a circle in standard form is

(x-a)² + (y-b)² = r²

where (a, b) are the coordinates of the centre and r is the radius

To obtain this form ' complete the square ' on both the x and y terms

x² + 2(1)x + 1 + y² + 2(3)y + 9  = 39 + 1 + 9

(x+1)² + (y+3)² = 49 ← in standard form

with centre (1, 3) and r = √49 = 7

7 units

Step-by-step explanation:

(h,k) = (-2/2, -6/2) = (-1,-3)

(-1)² + (-3)² - (-39) = r²

49 = r²

r = 7

part a

in a city ice cream is mostly only bought when the temperature is very high as ice cream cools down our

so we can derive the conclusion that as the temperature increases the number of ice creams sold also increases

part b

y intercept is 5

slope is 2

happy to

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