Question 213715This question is from textbook MATHPOWER 11
: Solve by elimination. Check each solution.
21. 6x-5y=-3
2y-9x=-1
Please help me out ive been stuck on this one for a while! This question is from textbook MATHPOWER 11
You can eliminate either the x or the y terms. In order to eliminate the y terms, you need a common multiple of the coefficients -5 and 2. That would be 10. You need to get a -10y in the first equation and a +10y in the second equation, which will make the y terms subtract out. So multiply the first equation by 2 and the second equation by 5 like this:
2(6x -5y) =2*-3
5(-9x+2y)=5*-1
12x -10y =-6
-45x +10y =-5
-33x=-11
Divide both sides by -33
x=1/3
Substitute x=1/3 back into the first equation:
6x-5y=-3
6*1/3-5y=-3
2-5y =-3
-5y=-5
y=1
Check in the second equation:
-9x+2y = -1
-9*(1/3) +2(1)=-1
-3 +2=-1
It checks!!
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Dr. Robert J. Rapalje, Retired
Seminole Community College
Altamonte Springs Campus
Florida
Solve: We'll use substitution. After moving -5*y to the right, we get: , or . Substitute that
into another equation: and simplify: So, we know that y=1. Since , x=0.333333333333333.
Answer: .
Step 6. Same result...the solution is and .
I hope the above steps were helpful.
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