SOLUTION: Solve by elimination method: (5/2) x + (10/3)y = 55 and (7/3)x + (7/2)y = 56 I know these two equations then equal: 15x+20y=330 and 14x+21y=336 But I don't know what to do fr

Algebra.Com
Question 1028377: Solve by elimination method:
(5/2) x + (10/3)y = 55 and (7/3)x + (7/2)y = 56
I know these two equations then equal:
15x+20y=330 and 14x+21y=336
But I don't know what to do from there! And what is elimination method anyway? What's the difference between that and substitution method or are they the same thing and are there any other kinds of methods?

Found 3 solutions by mananth, josgarithmetic, Shin123:
Answer by mananth(16946)   (Show Source): You can put this solution on YOUR website!
15x+20y=330
/5
3x+4y=66
14x+21y=336
/7
2x+3y=48
3 x + 4 y = 66 .............1

2 x + 3 y = 48 .............2
Eliminate y
multiply (1)by -3
Multiply (2) by 4
-9 x -12 y = -198
8 x + 12 y = 192
Add the two equations
-1 x = -6
/ -1
x = 6
plug value of x in (1)
3 x + 4 y = 66
18 + 4 y = 66
4 y = 66 -18.00
4 y = 48
y = 12
x= 6
y= 12
m.ananth@hotmail.ca


Answer by josgarithmetic(39621)   (Show Source): You can put this solution on YOUR website!
Elimination is just a fancy often more efficient way of handling Substitution.

Multiply each equation so you can eliminate y and solve for x; start over and multiply each equation to eliminate x and solve for y.

System starts as

You can simplify each of the equations before you start the elimination method process because each of your equations is still simplifiable. The factor 5 in one equation and factor 7 in the other.



You will want coefficient on y to become 12, which I will not explain...


, the system is equivalent to the first system (and to the second system).

This next step is two substitutions, USING the system...

.
.
...and what is x ?


Now, you can manage the process again to find y in similar manner.

Answer by Shin123(626)   (Show Source): You can put this solution on YOUR website!

RELATED QUESTIONS

we have been studying systems of nonlinear equations in two variables. Question: Solve: (answered by vertciel)
Please help me solve this problem: 1.) 3x+5/3y=19 and -5x^+2y=-11+7X 2.) -2Y^=-20Y+18 (answered by Alan3354)
I need to use elimination to solve each system of equations, and don't know how to do... (answered by sehar)
please i have a problem with the following equation and don't know how to go about it and (answered by ewatrrr)
I'm trying to solve a few equations that I just can not seem to understand, please... (answered by solver91311)
solve by elimination method 6x-y=3... (answered by robertb)
please help me solve these equations using elimination y=(1/3)x+2 and y=(5/2)x-1 (answered by solver91311,stanbon)
I don't know how to solve this! System of equations by the elimination method: x/2 +... (answered by TimothyLamb,MathTherapy)
Solve the system of linear equations by using the equal values method y=x+3 and y=2x-5 (answered by josgarithmetic)