SOLUTION: Is there anyone that can help? I don't understand how to do this. Solve the following system of line at equation by substitution and determine whether the system has one solution,

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Is there anyone that can help? I don't understand how to do this. Solve the following system of line at equation by substitution and determine whether the system has one solution,       Log On


   



Question 1072302: Is there anyone that can help? I don't understand how to do this. Solve the following system of line at equation by substitution and determine whether the system has one solution, no solution or an infinite number. If the system has one solution, find solution.
-2x-y=23
7x-2y=2

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
1) -2x-y = 23
2) 7x -2y = 2
:
solve equation 1 for y
:
-y = 2x +23
:
y = -2x -23
:
substitute for y in equation 2
:
7x -2(-2x -23) = 2
:
7x +4x +46 = 2
:
11x = -44
:
x = -4
:
y = -2(-4) -23 = -15
:
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x = -4 and y = -15
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Note that this solution is the point of intersection of the two equations that represent lines
:
check answer by substituting for x and y in equations 1 and 2
:
equation 1
:
-2(-4) -(-15) = 23
8 + 15 = 23
23 = 23
:
equation 2
:
7(-4) -2(-15) = 2
-28 +30 = 2
2 = 2
:
our answer checks
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