+130516 2p+5r=q for p subtract 5r from both sides
2p = [q - 5r] divide both sides by 2
p = [q - 5r] / 2
-10=y+z for x . there's no x here !!!!
a/b=c for b multiply both sides by b
a = bc divide both sides by c
a/c = b
h-4/j=k for j subtract h from both sides
-4j = k - h divide both sides by -4
j = [k - h] / -4 = [ h - k] / 4
