Can I please have help with this problem?

7. Let U1 and U2 be two upper-triangular matrices and let Z be an m x 1:. matrix. Let X be an unknown matrix that satises the equation U1X +X U2 = Z. A) Give an algorithm that nds X in 0(m n(m + n)) arithmetic operations. B) Find conditions on U1 and U2 that guarantee the existence of a unique solution X. C) Give a nontrivial example (U1 7&0, U2 34E 0 and X 34E 0) where those conditions are not satised and U1X+XU2=0