How to find the length when the perimeter and width is given

If f(x) = 6x – 4, what is f(x) when x = 8? a2 b16 c44 d52

The height of a plant, in inches, p years after planting it is given by the polynomial function r(p) = -2p% + 270p. find the height of the plant when p = 90 years.

Larger pets need to be transported in larger portable kennels. using a graphing calculator and the relationship between the width, length, and height, find the dimensions of a portable kennel whose volume is 7.4 ft3. the dimensions of a portable kennel can be expressed as width x, length x + 0.4, and height x − 0.2? what are the dimensions of a portable kennel with a volume of 7.4 ft3? use a graphing calculator to solve. round the dimensions to the nearest tenth.