(-12)/ [-7) + 5] - (-7) 4 Help me plz
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Answer:
33 copies were paperback and 12 were hardcover.
Step-by-step explanation:
Let h represent the number of hardcover copies and p represent the number of paperback copies.
We know that the total number of copies was 45; this gives us the equation
h+p = 45
We know that each hardcover copy is 7 ounces; this gives us the expression 7h.
We also know that each paperback copy is 5 ounces; this gives us the expression 5p.
We know that the total weight was 249 ounces; this gives us the equation
7h+5p = 249
Together we have the system
We will use elimination to solve this. First we will make the coefficients of the variable p the same; to do this, we will multiply the top equation by 5:
To eliminate p, we will subtract the equations:
Divide both sides by -2:
-2h/-2 = -24/-2
h = 12
There were 12 hardcover copies sold.
Substitute this into our first equation:
12+p=45
Subtract 12 from each side:
12+p-12 = 45-12
p = 33
There were 33 paperback copies sold.
ANSWER
EXPLANATION
Recall that,
That is why
is equivalent to
This implies that,
This is the same as,
When we are dividing by
we move the decimal point backwards two times.
This implies that,
EXPLANATION
Recall that,
That is why
is equivalent to
This implies that,
This is the same as,
When we are dividing by
we move the decimal point backwards two times.
This implies that,