Question

Given the equations and the table below, what is the first x-value when the y-value of equation 2 is greater than the y-value of equation 1 after the functions first intersect?Equation 1: f(x)=5x^3Equation 2: f(x)=2x+3A: x=14B: x=7C: x=17D: x=12

Answer 1

From what I explained in the session before, the x value must be between 10 and 15, so only 2 options are viable, 14 and 12. Let's evaluate each of them

$\begin{gathered} f(x)=5x^3 \\ f(12)=5(12)^3 \\ f(12)=5(1728) \\ f(12)=8640 \\ \\ f(x)=2^x+3 \\ f(12)=2^{(12)}+3 \\ f(12)=4096\text{ +3 = 4099} \end{gathered}$

So, 12 is not the answer. Let's evaluate 14

$\begin{gathered} f(x)=5x^3 \\ f(14)=5(14)^3 \\ f(14)=5(2744) \\ f(14)=13720 \\ \\ f(x)=2^x+3 \\ f(14)=2^{14}+3 \\ f(14)=16384+3 \\ f(14)=16387 \end{gathered}$

So, x = 14 is the correct answer