College Algebra Review

[Belby]

I have worked this problem a lot of times and cannot come up with the right answer. Please help fast and explain. Thanks.
If we simplify the expression
4(z/8) + z/6 as 8z/A what is the value of A? Note that 4(z/8) means 4 multiplied by (z/8).

 

[mmm4444bot]

I have worked this problem a lot of times and cannot come up with the right answer …

Too bad you didn't show some of that work. If you had, then we would be able to see where you're going wrong.

'

… Please help fast …

Okay, but can you keep up with me ?

Start by multiplying 4 by z/8.

Show me what you get.

 

[Belby]

4z/32

 

[wjm11]

If we simplify the expression
4(z/8) + z/6 as 8z/A what is the value of A?

4(z/8) + z/6 = 8z/A

First, let’s get rid of fractions; multiply both sides of the equation by 48A and simplify:

48A[4(z/8) + z/6] = 48A[8z/A]
24zA + 8zA = 384z
32zA = 384z
A = 12

Check:
4(z/8) + z/6 = 8z/12
z/2 + z/6 = 2z/3
3z/6 + z/6 = 2z/3
4z/6 = 2z/3
2z/3 = 2z/3 TRUE.

It works.

 

[Belby]

Thank you. I was not working it that way.

 

[mmm4444bot]

4z/32 This is not correct.

The rule for multiplying one fraction by another is "numerator times numerator over denominator times denominator".

\(\displaystyle \frac{4}{1} \cdot \frac{z}{8} = \frac{4 \cdot z}{1 \cdot 8} = \frac{4z}{8} = \frac{z}{2}\)

 

[Denis]

Please help fast and explain.

Would you like fries with that?