SOLUTION: 7x + 3y=5 6x - 4y=3

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Question 1042225: 7x + 3y=5 6x - 4y=3
Found 3 solutions by ikleyn, jorel555, Edwin McCravy:
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.
7x + 3y=5 6x - 4y=3
~~~~~~~~~~~~~~~~~~~~~~

A good style is to say "Please show me how to solve it . . . "

7x + 3y = 5,      (1)
6x - 4y = 3.      (2)

Multiply eqn.(1) by 4 (both sides) and the eqn.(2) by 3. You will get

28x + 12y = 20,   (1')
18x - 12y =  9.   (2')

Now add eqns(1') and (2'). You will get

46x = 29.

Hence,  x = 29%2F46.

Having x, now find y from either equation (1) or (2).

I applied here the Elimination method.
There are also the Substitution method and the Determinant method.
For these methods see the lessons
    - Solution of a linear system of two equations in two unknowns by the Substitution method
    - Solution of a linear system of two equations in two unknowns by the Elimination method
    - Solution of a linear system of two equations in two unknowns using determinant
    - Geometric interpretation of a linear system of two equations in two unknowns
    - Solving word problems using linear systems of two equations in two unknowns
in this site.


Answer by jorel555(1290) About Me  (Show Source):
You can put this solution on YOUR website!
7x+3y=5
6x-4y=3
So:
28x+12y=20
18x-12y=9
46x=29
x=29/46
y=9/46. ☺☺☺☺

Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!

Neither the good lady nor Jorel told you what the best
thing to do when you are solving a system of equations 
by the addition (or elimination) method and the answer 
to the first unknown or variable comes out to be a very 
difficult fraction such as x=29/46.  In such cases the 
best plan is NOT to substitute the bad fraction into one 
of the original equations. The best plan is instead to
start over and eliminate the variable x to find y.

They both showed you how to get x = 29/46.  But here is
what you should have done to get y:

Begin again and this time eliminate x



Multiply the first equation by -6 and the second equation
through by 7, (Or you could multiply the first equation 
by 6 and the second equation through by -7):



Adding the equations term by term gives the equation:

-46y%22%22=%22%22-9

y%22%22=%22%229%2F46

That's easier than substituting 29/46 for x in one
of the original equations and solving for y.

Edwin