The center of a circle is at (−3, 1) and its radius is 9. what is the equation of the circle? (x+3)2+(y−1)2=18 (x−3)2+(y+1)2=18 (x−3)2+(y+1)2=81 (x+3)2+(y−1)2=81

The standard form of the circle equation is in the form with the center being at the point and the radius being "r".

We have to find the equation of circle with center (-3,1) and radius as 9.

So, h= -3, k=1 and r=9

Equation of circle is:

is the required equation of the circle.

Therefore, Option 4 is the correct answer.

answer: a

step-by-step explanation:

if xy ~ yz therefore xy would be the same length as yz

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204