Question

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Answer 1

Answer:

Radius , r = 5 units

Step-by-step explanation:

The standard form of a circle's equation:

  $(x-a)^2 + (y -b)^2 = r^2 \ , \ where \ (a , b) \ is \ the \ centre\ and\ r \ is \ the \ radius.$

Given equation :

  $x^2 - 2x + y^ 2- 4y = 20$

Find radius .

Convert the given equation into standard form.

$(x - 1)^2 = x^ 2 - 2x + 1 \\\\(y - 2) ^2 = y^ 2 - 4y + 4$

Now add both equations :

  $(x - 1)^2 + (y - 2)^2 = r^2$

$(x ^ 2 - 2x + 1) + (y^2 - 4y + 4 ) = r^2\\\\(x^2 -2x + y^2 - 4y ) + 1 + 4 = r^2\\\\20 + 1 + 4 = r^2$          $[ \ given : \ x^2 - 2x + y^ 2 - 4y = 20 \ ]$

$25 = r^2 \\\\5 = r$

Answer 2

Answer:yo we talking the same test

Step-by-step explanation:

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