How to check if an equation is always, sometimes, or never true

What is the measure of ac? 5 units 13 units 26 units 39 units 3x- 2b 6x + 9

Acylinder with a base diameter of x units has a volume of jxcubic units which statements about the cylinder are true? check all that apply. the radius of the cylinder is 2 x units. the radius of the cylinder is 2x units. the area of the cylinder's base is 200 square units. the area of the cylinder's base is a square units. the height of the cylinder is 2x units. the height of the cylinder is 4x units. mark this and return save and exit next submit

Asequence is defined recursively using the formula f(n + 1) =f(n) - 5. which sequence could be