Question

the intersection of two planes is a line? true or false

Answer 1

The intersection of two distinct planes is a line, true.

These questions you are asking concern the very first postulates of Geoemetry.
Do read and review them.

Answer 2

ok thanks

Answer 3

Look for these or something similar:

•Postulate 1: A line contains at least two points.
•Postulate 2: A plane contains at least three noncollinear points.
•Postulate 3: Through any two points, there is exactly one line.
•Postulate 4: Through any three noncollinear points, there is exactly one plane.
•Postulate 5: If two points lie in a plane, then the line joining them lies in that plane.
•Postulate 6: If two planes intersect, then their intersection is a line.