(1) Introduce new variable u =. Then the equation becomes = 0 (u-1)*(u-25) = 0. It has two roots u = 1 and u = 25. The root u = 1 means that = 1, i.e. x = 0. The root u = 25 means that = 25, i.e. x = 2. ANSWER. There are two solutions 0 and 2. (2) This equation is presented in the STARNGE form in the post. I do not believe it is correct. Double check it (!) (3) = 0.125 = . x = -3. ANSWEWR (4) = 625 = 10x = 4 x = = 0.4. ANSWER