Shawna and her best friend Keisha together spend $ 138
Solution:
Given that, Shawna and her best friend Keisha go shopping.
The function given for money each girl spent based on the number of hours they were shopping is:
[tex]p(t)=3 x^{4}+2 x^{3}-4 x^{2}+21[/tex]
Find the amount of money that each girl spent
For t = 2 hours
[tex]\begin{array}{l}{\mathrm{p}(2)=3(2)^{4}+2(2)^{3}-4(2)^{2}+21} \\\\ {\mathrm{p}(2)=3 \times 16+2 \times 8-4 \times 4+21} \\\\ {\mathrm{p}(2)=48+16-16+21} \\\\ {\mathrm{p}(2)=69}\end{array}[/tex]
Find the amount of money that they spend together
Multiply by 2 the amount of money that each girl spent
[tex]2 \times 69 = 138[/tex]
