Answer:
f(x)=x^2+3
f(x+y)=(x+y)^2+3
this is done by replacing x with (x+y)
f(x+y)=x^2+2xy+y^2+3
therefore : f(x+y)= x^2+y^2+2xy+3
Answer:
(x - 10)² + (y + 9)² = 20
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
The radius is the distance from the centre to a point on the circle
To calculate r use the distance formula
r = √(x₂ - x₁ )² + (y₂ - y₁ )²
with (x₁, y₁ ) = (10, - 9) and (x₂, y₂ ) = (12, - 13)
r = 
=
=
, hence
(x - 10)² + (y - (- 9))² = (
)², that is
(x - 10)² + (y + 9)² = 20
Just add the numerators and the answer becomes (4/x–4)