Answer:
$69
Step-by-step explanation:
Given the amount of money each girl spent based on the number of hours they were shopping modeled by the function p(x) = 3x4 + 2x3 − 4x2 + 21
To get how much they spend together if each go shopping for 2hours, we will substitute x = 2 into the given function as shown:
p(2) = 3(2)⁴ + 2(2)³ − 4(2)² + 21
p(2) = 3(16) + 2(8) − 4(4) + 21
p(2) = 48 + 16 − 16 + 21
p(2) = 48+21
p(2) = 69
Therefore they spend $69 together
