Equations of geometric shapes

Equation of a line
ax + by + c = 0
Find   It is known that:
      =   

Equation of a line (slope-intercept)
y = kx + l
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      =   

Equation of a line (point-slope)
y - y1 = k(x - x1)
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      =   

Equation of a line from two points
(y - y1) / (y2 - y1) = (x - x1) / (x2 - x1)
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Equation of a circle whose center is at (x0, y0)
(x - x0)^2 + (y - y0)^2 = R^2
Find   It is known that:
      =   

Equation of a circle whose center is at the origin
x^2 + y^2 = R^2
Find   It is known that:
      =   

Equation of a sphere whose center is at (x0, y0, z0)
(x - x0)^2 + (y - y0)^2 + (z - z0)^2 = R^2
Find   It is known that:
      =   

Equation of a sphere whose center is at the origin
x^2 + y^2 + z^2= R^2
Find   It is known that:
      =