explain why there must be at least two lines on any given
plane,

there must be at least two lines on any plane because a plane is defined by 3 non-collinear points. Explanation: ... These lines may or may not intersect. If two of the 3 points are collinear, then we have a line through those 2 points as well as a line through the 3rd point.

f(2x−x2)=−3x2+6x−1

step-by-step explanation:

set up the composite function and evaluate.

f(2x−x2)=−3x2+6x−1