SOLUTION: Trying to help my duaghter with the folowing problem. one side will be 5x+y = 7 the other side is 3x-4y=18 We need to slove for x and y. Thanks for any help.

Algebra ->  Parallelograms -> SOLUTION: Trying to help my duaghter with the folowing problem. one side will be 5x+y = 7 the other side is 3x-4y=18 We need to slove for x and y. Thanks for any help.      Log On


   

Question 281309: Trying to help my duaghter with the folowing problem.
one side will be 5x+y = 7 the other side is 3x-4y=18 We need to slove for x and y.

Thanks for any help.
Found 2 solutions by richwmiller, stanbon:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
For a parent, there are a lot of words spelled wrong.
duaghter
folowing
slove
Concentrate on your spelling if you really want to help your daughter.
You gave expressions for two sides but didn't say what the figure is.
The category you used is parallelograms.
If the figure is a a parallelogram there is not enough info.

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Trying to help my duaghter with the folowing problem.
one side will be 5x+y = 7
the other side is 3x-4y=18 We need to solve for x and y.
--------------------------------
5x+y = 7
3x-4y = 18
-----------------
Two popular methods for solvin "systems" of equations
are substitution and elimination.
-----
I'll show you both ways since your daughter may not have
been introduced to one or the other.
-------------------------------------------------------------------------
Substitution:
5x+y = 7
3x-4y = 18
---------------
Solve the 1st equation for "y":
y = -5x+7
------
Substitute for "y" in the 2nd equation:
3x - 4(-5x+7) = 18
3x + 20x - 28 = 18
23x - 28 = 18
23x = 46
x = 2
----------------------
Subtitute for x in the equation y = -5x+7
y = -5(2)+7
y = -10+7
y = -3
----------------------
Final Answer: (2,-3)
=================================================================
Elimination:
5x+y = 7
3x-4y = 18
-------------------
Multiply both sides of the 1st equation by 4 to get:
20x + 4y = 28
3x - 4y = 18
--------------
Add to get:
23x = 46
x = 2
-----------------------
Substitute that value of "x" into either of the
original equations and solve for "y":
5x+y = 7
5*2+y = 7
10+y = 7
y = -3
------------------------
Final Answer: (2,-3)
========================================
Cheers,
Stan H.