Use the given information to write the standard equation of the circle. 7. a circle with center (1, 2) and radius 5 8. a circle with center (-3, 5) and radius 2 9. Write the standard equation of a circle that is tangent to the x-axis, with the center located at (2,4) 10. Write the standard equation of a circle with the center at (-1,-4) that passes through the point (-1,-1)