Answer:
$456
Step-by-step explanation:
Given the cost of producing a rectangular container whose top and bottom are squares with side x feet and height 6 feet expressed by the polynomial function
C(x) = 6x²+90x
To find the cost of producing a box with x = 4feet, we will substitute x = 4 into the function as shown;
C(4) = 6(4)²+90(4)
C(4) = 6(16)+360
C(4) = 96+360
C(4) = 456
The cost is $456