Greatest common factor of 50ab, 200a

With math question will mark brainliest question in the pic.

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

Which value would be a solution for x in the inequality 47-4x< 7