Which of the following is the equation of a circle whose center is at the origin and whose diameter has end (-1,2) and (1,-2)

x² + y² = 5

Step-by-step explanation:

The circle with center (h, k) and radius r has equation ...

... (x -h)² + (y -k)² = r²

You can find r² using the Pythagorean theorem or the distance formula, or you can simply calculate what it needs to be to make one or the other of the points lie on the circle.

For (h, k) = (0, 0), the equation is ...

... (x -0)² + (y -0)² = r²

Using (-1, 2) for (x, y), we can find r² as ...

... (-1 -0)² + (2 -0)² = r² = 1 + 4 = 5

Then the circle equation is ...

... x² + y² = 5

468

step-by-step explanation:

b

step-by-step explanation:

the equation of a line in point- slope form is

y - b = m(x - a)

where m is the slope and (a, b) a point on the line

calculate m using the slope formula

m = (y₂ - y₁ ) / (x₂ - x₁ )

with (x₁, y₁ ) = (0, 4) and (x₂, y₂ ) = (3, - 5) ← 2 points on the line

m = = = - 3

with m = - 3 and (a, b) = (3, - 5), then

y - (- 5) = - 3(x - 3), that is

y + 5 = - 3(x - 3) → b