Which shows 2.6x10^4 in standard notation

The general form of the quetion of a circle is ax^2+by^2+cx+dy+e=0 where a=b=0 if the circle has a radius of three units and the center lies on the y axis which set of values of a, b, c, d, and e might correspond to the circle

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?

What is an alternate exterior angle