The number of computers sold by BCC depends on the dollar amount, x, that they spend on advertising. How much must they spend to sell 200 computers? Round to the nearest dollar and do not include units in your answer.
N(x) = 100 + 20 ln(0.25x)

Question

The number of computers sold by BCC depends on the dollar amount, x, that they spend on advertising. How much must they spend to sell 200 computers? Round to the nearest dollar and do not include units in your answer.
N(x) = 100 + 20  ln(0.25x)

science0229 · Answer

Basically, you solve the equation 200=100+20 ln(0.25x).
Subtract 100 from both sides, then divide by 20, which gives you 5=ln(0.25x)
According to the definition of ln, $$y=\ln(f(x))\leftarrow \rightarrow f(x)=e ^{y}$$
So, $$0.25x=e ^{5}$$.
Divide both sides by 0.25, and you'll get $$x=4e ^{5}$$
You then round it to the nearest dollar, which I'll leave it up to you.