Answer: the answer is 6)
Step-by-step explanation:
Because .
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I hope it right
1. Jane saved up 20 coins, all nickels and
1 answer:
Answer:
10 nickels and 10 quarters
Step-by-step explanation:
Given
Number of coins: 20
Vaiue of coins = $3.00
Required
Number of Nickels and Quarters;
<em>Let N =Nickels and Q =Quarters</em>
The total coins is represented as:
1 nickel is equivalent to $0.05 and 1 quarter is equivalent to $0.25; So
Make N the subject of formula in the first equation
Substitute this in the second equation
Collect like terms
Multiply both sides by 5
Recall that N = 20 - Q
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Answer:
(x, y, z) = (3, -2, 4)
Step-by-step explanation:
The attachment shows a solution using a graphing calculator where the first equation is solved for z, and that expression is substituted into each of the other two equations. The solution to that system is (x, y) = (3, -2). Using these values in the expression for z, we find ...
z = 5 -(3 +(-2)) = 4
The solution is (x, y, z) = (3, -2, 4).
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Your graphing calculator and/or online tools can give you the reduced row echelon form of the augmented matrix representing the system:
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If you're solving by hand, you can do the substitution described above to eliminate z from one equation. You can eliminate z from another equation by adding the last two:
-3x -4y +4(5 -x -y) = 15 ⇒ -7x -8y = -5
(-3x -4y +4z) +(2x -y -4z) = (15) +(-8) ⇒ -x -5y = 7
This pair of equations can be solved for x and y in any of the usual ways. Using the second equation to substitute for x, for example, gives you ...
-7(-5y -7) -8y = -5 ⇒ 27y = -54 ⇒ y = -2
x = -5(-2) -7 = 3
z = 5 -(3) -(-2) = 4
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<em>Additional comment</em>
If all that is needed is a solution, we prefer a graphical or matrix approach. These take about the same amount of time. Both require a little additional effort to determine exact values when the solutions are not integers.
