SAT Mathematics Practice Test 3

Substituting 25 for y in the equation y = (x − 11)2 gives $25=\left(\mathit{x}-11\right)2$ .
It follows that $\mathit{x}-11=5$ or$\mathit{x}-11=-5$,
so the x-coordinates of the two points of intersection are x = 16 and x = 6, respectively.
Since both points of intersection have a y-coordinate of 25, it follows that the two points are$\left(16,25\right)$and $\left(6,25\right)$.
Since these points lie on the horizontal line $\mathit{y}=25$, the distance between these points is the positive difference of the x-coordinates: $16-6=10.$
Choices B, C, and D are incorrect and may be the result of an error in solving the quadratic equation that results when substituting $25$ for $\mathit{y}$ in the given quadratic equation