To get common denominators, you need to find the GFC (greatest common factor) of 5 and 6, which is 30. Then you would need to make the fractions equal the same as the original fractions, by multiplying.
2/5 = ?/30 <- you can see that 30 is 6 times more than 5. so this means you multiply 2 by 6 to get 12. 12/30
5/6 = ?/30 <- you can see that 30 is 5 times more than 6. so this means you multiply 5 by 5 to get 25. 25/30
Explanation: A plane contains at least three non-collinear points. If two points lie in a plane, then the line containing them lies in the plane. If two planes intersect, then their intersection is a line.