SOLUTION: I'm trying to figure this equation out. Solving using the elimination method. I need to identify the solution. 3x-6y equals 0 and 2x+4y=5. I am so stuck and confused on two or

Question 29755: I'm trying to figure this equation out. Solving using the elimination method. I need to identify the solution. 3x-6y equals 0 and 2x+4y=5. I am so stuck and confused on two or more elimination methods. Either it's my instructor or I'm trying to decide which to eliminate first. The y, x or z first?

Answer by sdmmadam@yahoo.com(530) (Show Source): You can put this solution on YOUR website!
I'm trying to figure this equation out. Solving using the elimination method. I need to identify the solution. 3x-6y equals 0 and 2x+4y=5. I am so stuck and confused on two or more elimination methods. Either it's my instructor or I'm trying to decide which to eliminate first. The y, x or z first?
3x-6y = 0 ----(1)X2
2x+4y = 5 ----(2)X3
Therefore
6x-12y = 0 ----(3) (zero mulitplied by anything is zero)
6x+12y = 15 ----(4)
(3) +(4) implies
(6x+6x) = (0+15)
12x = 15
x = 15/12 = 3X5/3X4 = 5/4
Putting x = 5/4 in (2)
2x+4y = 5
2X(5/4)+4y =5
Multiplying by 4 through out
10+16y =20
16y =20-10
16y = 10
y = 10/16 = 5/8
Answer: x=5/4 and y= 5/8
Verification: Putting x=5/4 and y= 5/8 in (1)
3x-6y = 0 ----(1)
LHS = 3x-6y = 3X(5/4)-6X(5/8) = (15X2-6X5)/8 = (30-30)/8 = 0/8 = 0 = RHS
(finding the lcm of 4 and 8)

Note: First of all there is no z here.
x and y are the two unknowns and there are two equations in x and y,
which is fine and which is what we want to find x and y.
And there is no hard and fast rule that we have to find x first
and y next or vice versa.
Studying the problem which ever variable is easily removable,we decide upon eliminating that first and finding the other variable first. For example in some problems a particular variable will have coefficient = (1) or (-1) in which case it is easy to handle that variable for elimination and find the value of the other variable first.
When both variables have coefficients other than +1 or -1,
we select that variable whose coefficients have opposite signs,
find the lcm of the coefficients and multiply the equations by suitable numbers to equalise the numerical coefficients which after the above treatment are equal in magnitude and opposite in sign and offer ready elimination on addition (which is much more preferable to subtraction which is the procedure when coefficients are equal in magnitude and in sign)
RELATED QUESTIONS
I need help solving the following using the substitution method and the elimination... (answered by ankor@dixie-net.com)

I need help solving this equation using the elimination method: x+6y=79... (answered by ankor@dixie-net.com,ReadingBoosters)

I am trying to figure out how to solve this math equation: 4x - (3x + 5) = -2 It... (answered by josgarithmetic,Shin123)

I need help solving this equation using the elimination method. {{{4x+5y=3}}}... (answered by jim_thompson5910)

my question: y is less than or equal to -x-2 . i am trying to figure out what y and x... (answered by josmiceli,josgarithmetic)

8x+5y=177.50 12x+6y=255.00 I need help solving this by either the substitution... (answered by Alan3354,MathTherapy,greenestamps)

I need help solving this please. Solve using the elimination method. Show your work.... (answered by Alan3354)

Sorry, I sent this the first time and forgot to type the problem. I need help with... (answered by priya)

Please help!! I need answers to the following questions, I really need to past this... (answered by sudhanshu_kmr)