Well we are confused too, because we don't know whether you mean:
or
Because you didn't use parentheses to indicate whether that first z is in the denominator of the first fraction or not. You should have written 3/(5z) + 4/z = 1 or (3/5)z + 4/z = 1.
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Further clarification indicates you meant:
Multiply by
Reduce the fractions:
Multiply by
John
My calculator said it, I believe it, that settles it
