Question 632979: 4x-y=5
9x-2y=13
Answer by lenny460(1073)   (Show Source):
You can put this solution on YOUR website! 4x-y=5
9x-2y=13
4x - y = 5 (1)
9x - 2y = 13 (2)
Let's take the first equation:
4x - y = 5
Add y to each side of the equation.
4x - y + y = 5 + y
Combine like terms:
-y + y = 0
Therefore:
4x = 5 + y
Divide each side by 4
4x/x = (5 + y)/4
x = (5 + y)/4
Substitute x = (5 + y)/4 into the second equation:
9x - 2y = 13
9(5 + y)/4 - 2y = 13
Multiply each item above by 4
9(5 + y)/4 * 4 - 2y * 4 = 13 * 4
9(5 + y)/4 * 4 = 9(5 + y)
9 * 5 = 45
9 * y = 9y
-2y * 4 = -8y
13 * 4 = 52
Therefore:
45 + 9y - 8y = 52
Combine like terms:
9y - 8y = 1y
45 - 1y = 52
Subtract 45 from each side of the equation.
45 - 1y - 45 = 52 - 45
Combine like terms:
45 - 45 = 0
52 - 45 = 7
1y = 7 or
y = 7
Substitute y = 7 into equation 1
4x - y = 5
4x - 7 = 5
Add 7 to each side of the equation.
4x - 7 + 7 = 5 + 7
Combine like terms:
-7 + 7 = 0
5 + 7 = 12
4x = 12
Divide each side by 4
4x/4 = 12/4
x = 3
The Answer:
x = 3
y = 7
Lennox Obuong
Algebra Student
Email: obuong3@aol.com
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