Iam a prime number greater than 40 and less than 90. my units digit and my tens digit are both prime. the difference between my units digit and tens digit is not 2. what number am i?

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

Solve the equation -9p - 17 =10 a -3 b. 16 c. 18 d -16

20 solve 2(4 x + 3) < 5 x + 21. a) { x | x < 9} b) { x | x > -5} c) { x | x > -9} d) { x | x < 5}