1800 m of fencing is available to fence six identical pens as shown.
a. explain why 9x+8y=1800
b. show the total area of each pen is given by a=-(9/8)x^2+225x
c. if the area enclosed is to be maximised, what is the shape of each pen?

I am not sure if i understand

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)