Solve the system of equations by the addition method. x- y=-9 x+y=-5
1 answer:
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Answer:
(x + 4)² + (y + 5)² = 73
Step-by-step explanation:
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
here (h, k) = (- 4, - 5), thus
(x - (- 4))² + (y - (- 5))² = r², that is
(x + 4)² + (y + 5)² = r²
The radius is the distance from the centre to a point on the circle.
Calculate r using the distance formula
r = √ (x₂ - x₁ )² + (y₂ - y₁ )²
with (x₁, y₁ ) = (- 4, - 5) and (x₂, y₂ ) = (4, - 2)
r =
=
= =
⇒ r² = 73, thus
(x + 4)² + (y + 5)² = 73 ← equation of circle