Find the simple interest on #600.00 for 5 years at 90%

Need solving this second acceleration problem.

Miranda is braiding her hair.then she will attach beads to the braid.she wants 1_3 of the beads to be red.if the greatest number of beads that will fit on the braid is 12,what other fractions could represent the part of the beads that are red?

For f(x)=2x+3 and g(x)=x^2- 8 find (f+g) (x)