College Algebra question from REA book

[joel66]

I took my first practice test on REA, scored 66

On question 29 of 60 for test 1, I am completely lost. lol

Question:
If xy-3=20 and y-3=5, then x=

The answer is 3.

Under the explanation, it gives the following steps:

xy-3x=20

Factor:
x(y-3)=20

Substituting (y-3)=5

X(5)=20

Dividing both sides by 5:

X=4

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My question, it shows the first step under the explanation xy-3x=20. Where did the other x come from? I noticed they placed an x behind 3.

[gcalvin]

Yep, that's a mistake. I've never used the REA materials, but from what I hear, it's not unusual to find mistakes in them.

-Gary-