Question 151790: Hi,
I need help with the following: I did the work just want to make sure its right
.Explain how to apply elimination in solving a system of equations.
To solve a system of linear equation by elimination process
1)Bring the co-efficient of any one variable to the same .
2) If the signs of both variable are same (having the same co-efficient) then subtract the two equation's.
a. Explain how to apply substitution in solving a system of equations.
3)If the signs are different then add the two equation’s so that like terms get eliminated.
4)The value of one variable is calculated
5)By substituting the value of known variable unknown variable can be found.
a. Demonstrate each technique in solving the system
3x + 9y = 12
5x - 4y = 3
Solution: 1. 3x + 9y = 12
2. 5x - 4y = 3
1)L.C.M of 3,5 = 15 hence bring the co-efficient of x to 15
multiply equations(1) by 5 , and equations(2) by 3. The two equations
reduces to 15x+45y = 60
15x-12y = 9
2) subtract the two equations we get 57y = 51 , y = 51/57
3) substituting the value of y in equations
(1) we get
3x+9(51/57) = 12
3x = 12- (459/57) = 684-459/57 = 225/57
x = 225/57*3 = 75/57
solution is x = 75/57 and y = 51/57
Thank you for your help.
S
Answer by vleith(2983)   (Show Source):
You can put this solution on YOUR website! You have the correct answers.
You can easily check you answers by just plugging the value for x and y into the original two equations and verifying the result is "true" (that is 12=12 and 3=3)
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