Let's try to create two equations to help us solve this problem. For this problem, 
will represent the number of nickels and 
will represent the number of quarters.
A first one could represent the number of <em>coins </em>we have. This does not regard the value of the coins, but rather just how many we could <em>count</em>. Based on the information in the problem, we could say:
After all, the number of nickels is 12 more than the number of quarters.
Now, let's create an equation to represent the value of the coins we have. Since each nickel is worth 5 cents, we can say the value of all the nickels in cents is 
. We can thus say for quarters that the value of all quarters in cents is 
. Since we know the value of the coins we have adds to $5.40, or 540 cents, we can say:
Now, we have two equations:
We can use substitution to find our answers:
We have now found that the number of quarters we have is 16. When we use this value in one of our equations, we can find :
We have 16 quarters and 28 nickels.
Answer:
11 and a 1/2
Step-by-step explanation:
I'm not sure if this is correct but here is my reasoning....
per every 1 there are two 1/2's so multiply 5x2 to get 10.
next, 1/2 is equivelent to 2/4 so subtract 3/4-2/4 (adding another 1/2 to our previous answer of 10 to get 11) and you have 1/4 left.
lastly, since 1/4 is half of 1/2, add 1/2 to 11 to get the final answer of 11 and a 1/2.
there are 11 and a half 1/2's in 5 and 3/4.
#13:
s² = 144
√(s²) = √144
|s| = 12
s = -12 OR s = 12
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#15 (not sure what letter you used so I went with 'g')
(g-6)² = 25
√[(g-6)²] = √25
|g-6| = 5
g - 6 = -5 OR g - 6 = 5
g = 1 OR g = 11
