
Hi, my name is Ashley. I'm in 7th grade (Prealgebra) Student question.
I've got 2 questions. We (my dad and I) can not figure them out. please help me.
 21 = 9  2 (4a + 2) and I am supposed to find out what the variable is.
 2/3 n + 3/8 n = 15/16 (those are fractions). Again, I need to find out what the variable is.
Thank you very much for your help.
Sincerely,
Ashley
Hi Ashley,
 I would first work with the right side of the equation. Multiply 2 by 4a + 2 to get
21 = 9  2 (4a + 2)
21 = 9 8a  4
Since 9  4 is 5 so this becomes
21 = 5  8a
Now, using the "balance" analogy for an equation, you can subtract 5 from both sides and maintain the balance. Thus
21  5 = 5  8a  5
16 =  8a
Now can you find a?

Twothirds of n plus threeeights of n is twothirds plus three eights of n. That is
2/3 n + 3/8 n = 15/16
is
(2/3 + 3/8) n = 15/16
Add 2/3 and 3/8 by first finding a common denominator, and then see if you can find n.
Cheers,
Penny
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