What is the correct evaluation of 3x2 + 4x - 2y2 + 4y + 5, when x is equal to -1 and y is equal to 5?
1 answer:
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Answer:
The student incorrectly simplified .
Thus, option D is correct.
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Step-by-step explanation:
The formula to determine the Perimeter of a rectangle of width w and length l is expressed as:
In other words, the perimeter can be determined by multiplying the length and width by 2 and adding the result.
In our case, the dimensions of a rectangle are and
.
Here is the student's solution:
The student made an error in calculating , because
are not like terms.
Hence, can not be simplified to
Therefore, the student incorrectly simplified .
Thus, option D is correct.
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<u>Here is the correct Solution:</u>
Answer:
a) total cost of m apples= $12 = 1200 cents
($1= 100cents, so $12= 12×100 cents)
cost of each apple= 1200/m
b) Number of apples sold= m-3
selling price of each apple= (1200/m) +2
Total sum received from sales:
c) profit= amount received- amount spent on buying apples
96= 2m +1194 -3600/m -1200
2m -6 -96 -3600/m =0 (simplify, bring 96 over)
2m- 102 -3600/m =0
2m^2 -102m -3600 =0 (multiply by m on both sides)
m^2 -51m -1800 =0 (divide by 2 on both sides)
(shown)
d) m^2 -51m -1800=0
Hence, using the above formula,
e) Thus, selling price of each apple
= 1200/75 +2
= 18 cents
This is found by substituting the value of m, which is 75, into the equation of the selling price of each apple which we found earlier in part b.
note: do not reject m= -24 in part d because you are simply solving the equation not finding out the number of apples the trader bought, m.
We ignore m= -24 in part e as it is not possible for the number of apples bought be a negative number