Can somebody help me with this I don’t get it?

Kapil needed to buy a long wooden beam. he went to two sawmills that each charge an initial fee plus an additional fee for each meter of wood. the following equation gives the price (in dollars) of a wooden beam from the first sawmill as a function of its length (in meters). p = 5+20xp=5+20x

The measures of the legs of a right triangle are 15m and 20m . what is the length of the hypotenuse

Which polynomial is in standard form? 3xy+6x®y2 - 4x4y + 19x? y* 18x5 - 7x{y-2xy2 + 1774 x5y5 - 3xy - 11x? y2 +12 15+ 12xy2 - 11x®ys +5x? y2 ?