Answer: Linear pairs angles are those formed in the same side of a line, when two lines intersect, these angles are always supplementary, that means that their addition equals 180º. In the image, the linear pairs formed by the intersection of the lines "a" and "c" are 1-2, 1-5, 2-6 and 5-6, notice that each pair is in the same side of a line just separated by the other one.
Same-side interior angles are those formed when two parallel lines are intersected by a third one, this angles are supplementary to. In the image, the lines "a" and "b" are parallels and are intersected by "c", the same-side interior angles are 2-3, notice that they are in the same side of "c" and they are both in the interior of the parallels.
So in summary, similarities: they are both supplementary an on the same side of a line.
Differences: The linear pairs are formed by two lines that intersect each other, the same-side interior angles are formed in the interior of two parallel lines intersected by a third one
