Recall that one of several equivalent definitions of a module $E$ being injective is that every short exact sequence starting with $E$ splits (exercise: prove this is equivalent to all other definitions you know).
Recall further the definition of a semisimple ring- a ring is semisimple iff all of its modules are a BLANK of BLANKS. In particular, every short exact sequence behaves like BLANK.
Combining these two statements, you should be able to prove what you want.
NOTE: Blanks have been used to help you find the answer on your own!