1.Sketch the circle whose equation isx²+ y²= 100. Using the same system of coordinate axes, graph the linex+ 3y= 10, which should intersect the circle twice: at A = (10, 0) and at another point B in the second quadrant. Estimate the coordinates of B. Now use algebra to find them exactly. Segment AB is called achordof the circle.

2.Draw the circlesx²+y²= 5 and (x- 2)²+ (y- 6)²= 25 on the same coordinate- axis system. Subtract one equation from the other, and simplify the result. This should produce a linear equation; graph it. Is there anything special about this line? Make a conjecture about what happens when one circle equation is subtracted from another.

3.Find an equation for the line that goes through the two intersection points of the circle

x²+y²=25 and the circle(x-8)^2+(y-4)²=65.