Test 3 Section 3 Number 10 please

There are a couple ways to think about this one. First, you can plug 25 in for *y* and solve for the two *x* values:

From there, you know that either or , so *x* must be 16 or 6. 16 and 6 are 10 apart, so the line that connects the two intersections of the parabola and the line must be 10 apart.

The other way to go is more abstract. Basically, you can think about the general shape of a parabola with a leading coefficient of 1, and the fact that is really just the parabola shifted 11 units to the right. A right or left shift won’t change the distance between the two points that intersect the graph at all, so you can think about the parabola instead. You know that’s going to hit when *x* equals 5 or –5, and 5 and –5 are 10 units apart.