Answer:
Part a) [tex]P=(12h+2)\ yd[/tex]
Part b) The expression that represent the cost of fencing the field is [tex](336h+56)[/tex]
Part c) [tex]\$1,736[/tex]
Step-by-step explanation:
The complete question in the attached figure
Part a) we know that
The perimeter of the rectangular field (excluding the width of the gate) is equal to
[tex]P=2(L+W)-4[/tex]
we have
[tex]L=(3h+3)\ yd\\W=3h\ yd[/tex]
substitute the given values
[tex]P=2(3h+3+3h)-4[/tex]
[tex]P=2(6h+3)-4\\P=12h+6-4\\P=(12h+2)\ yd[/tex]
Part b) we know that
To find out the cost of fencing the field (excluding the gate) , multiply the perimeter by the cost of $28 per yard
so
[tex]28(12h+2)=336h+56[/tex]
Part c) we have
h=5
substitute the value of h in the expression of the cost
[tex]336(5)+56=\$1,736[/tex]