write the equation of the circle in standard form

9. center at (-2, -4) and tangent to the x-axis 10. center at (5, -2) and tangent to the y-axisandard form. 6. center at the origin and diameter is 36 cm 7. center at (5, 4) and radius is 15 cm 8. center at (-4, 8) and passing through the point (1, 4)