Test 4 Section 3 #13

You’re told that the given parabolas intersect at and . Important insight: when two graphs intersect at a point, *that point is on both graphs*. Therefore, we don’t need to use both equations to solve this question, we can just pick one and find the values of *x* that will result in a function value of zero.

The given figure tells you that is positive (look where and are on the *x*-axis) so you know the answer is .

Note: You can also backsolve this one. Put the answer choices into one of the functions until you get a result of 0. Even without a calculator, that won’t take long (but will probably take longer than the algebra unless you’re stuck).