Question

if c is between a and b then ac + cb = ab. sometimes always never

Explanation:

When a point \( C \) lies between points \( A \) and \( B \) on a line segment, by the segment addition postulate in geometry, the sum of the lengths of \( AC \) and \( CB \) is equal to the length of \( AB \), i.e., \( AC + CB=AB \) always holds.

Answer:

always