**TI83F* AppVariable file 04/07/08, 14:107 &MC203&$nav F441BD13B950415AA7EB861D73925D5FMC203.MC2031  formula›formula:ÖAn equation that states a rule for the relationship between certain quantities.ÖExample:ÖA = Är^2 is the formula for finding the area of a circle. linear equationllinear equation:ÖAn equation in the form Ax + By = C, where A  0 and B  0, whose graph is a straight line.  perimeter 9perimeter:Öthe distance around a closed geometric figure. two-step equation@two-step equation:Öan equation having two different operations. í°