Question

find the following sum: 7z/15x+4z/9x

Answer 1

Find the common denominator, which is 45x. Then you multiply the numerator and denominator of both terms by the appropriate number to get 45x as the denominator.

(3*7z)/(3*15x) + (5*4z)/(5*9x)
= 21z/45x + 20z/45x
= 41z/45x

Answer 2

\[\frac{41 x z}{45} \]
http://www.wolframalpha.com/input/?i=simplify7+z%2F15+x+%2B+4+z%2F9+x&t=sftb01

Answer 3

That's true, but I think they meant to have x in the denominator. Mind you I guess my solution is just as ambiguous...ah the joy of brackets...

Answer 4

Starting today, I will warn them that the normal precedence rules will be applied if no parentheses or brackets are applied.