What is the range of possible side x?

In simplified exponential notation, the expression a^2•a^-3•a 1/a 0

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?

Which statements are true about additional information for proving that the triangles are congruent check all that apply