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Solve the below system of equations using the best method. Please describe the method used [substitution, graphing, elimination, etc], and give your answer in the form (x,y). 1.) 5x - 2y = -1 8x + 4y =
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Oct 3, 2018
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Solve the below system of equations using the best method. Please describe the method used [substitution, graphing, elimination, etc], and give your answer in the form (x,y).
1.) 5x - 2y = -1
8x + 4y = 56
2.) 3x - y = -16
-4x - y = 21
Mathematics
high-school
LaGuille
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1). Since you have -2y and 4y, elimination is easy to do for solving for x..
Keep the first equation and multiply the second equation by 2. Then add.
5x - 2y = -1
8x + 4y = 56
10x - 4y = -2
8x + 4y = 56
-----------------
18x = 54
x = 3
Now we can use substitution to solve for y.
Substitute 3 for x in the first original equation and solve for y.
5x - 2y = -1
5(3) - 2y = -1
15 - 2y = -1
-2y = -16
y = 8
(3, 8)
2.)
3x - y = =16
-4x - y = 21
Multiply both sides of the first equation by -1 to change all signs. Then when you add the equations, you eliminate y and solve for x.
-3x + y = 16
-4x - y = 21
-----------------
-7x = 37
x = -37/7
Now multiply the first original equation by 4 and the second original by 3 to eliminate x and solve for y.
12x - 4y = -64
-12x - 3y = 63
---------------------
-7y = -1
y = 1/7
Solution: (-37/7, 1/7)
Slex
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Oct 10, 2018
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Slex
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