What is the fastest way to do test 5 #14 from the no calculator section?

One tricky bit of business in this question is that it gives you f(x) and then asks what the graph of -f(x) looks like. They’re not being as mean as they could be, though: none of the answer choices are what f(x) should look like, so even if you’re not reading carefully at first, you should be able to clear that first hurdle no problem. Anyway, if f(x)=2^x+1, then -f(x)=-2^x-1.

When you need to figure out what a graph should look like without the aid of your calculator, try to pick a few easy points to calculate and use those to eliminate choices. If you look at the answer choices here, for example, you’ll notice that most of them have different y-intercepts, so start by plugging x = 0 to find the y-intercept you seek.


=-1-1 (Remember, anything to the 0 power is 1!)


Only choice C has a y-intercept of –2, so that must be the answer!

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