It is given that (2x−5)o and (x−10)o are the complementary angles.We know that, if two angles are complementary, then their sum is 90o.Then, (2x−5)o+(x−10)o=90o⟹ 2x−5o+x−10o=90o⟹ 3x−15o=90o⟹ 3x=15o+90o⟹ 3x=105o⟹ x=3105o​⟹ x=35o.Therefore, the value of x for which the angles (2x−5)o and (x−10)o are the complementary angles is 35o.