# How do you find the equation of a circle whose centre lies on the line 2x+y-1=0 and which passes through the point A(-2,0) AND B(5,1)?

##### 1 Answer

Please see the explanation for the process.

#### Explanation:

The standard form for the equation of a circle is:

where

Use the standard form to write two equations using points A and B:

Because

Expand the squares using the pattern

Combine like terms (noting that the squares cancel):

Move the k term the left and all other terms to the right:

Divide by 2

Evaluate the given line at the center point:

Write in slope-intercept form

Subtract equation [2] from equation [1]:

Substitute 2 for h in equation [2]

Substitute the center

Substitute the center