SOLUTION: 2/x-5/y=5 3/x+10/y=18 find the point where they intersect?

Algebra.Com
Question 1049120: 2/x-5/y=5
3/x+10/y=18
find the point where they intersect?

Found 3 solutions by josgarithmetic, MathTherapy, ikleyn:
Answer by josgarithmetic(39618)   (Show Source): You can put this solution on YOUR website!
Try just solving through substitution. Take one equation and solve for one variable. Substitute for this variable in the other equation. Solve for the single variable's value. Now find the value of the other variable, either equation.

Here is a start.





You continue the necessary steps for the process..

Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!

2/x-5/y=5
3/x+10/y=18
find the point where they intersect?
Easiest method: ELIMINATION
2y - 5x = 5xy -------- eq (i)
3y + 10x = 18xy ------ eq (ii)
4y - 10x = 10xy ------ Multiplying eq (i ) by 2 ------- eq (iii)
7y = 28xy ---- Adding eqs (iii) & (ii)


------- Substituting for x in eq (ii)

6y + 5 = 9y ----- Multiplying by LCD, 2
5 = 9y - 6y
5 = 3y

Answer by ikleyn(52790)   (Show Source): You can put this solution on YOUR website!
.
2/x-5/y=5
3/x+10/y=18
find the point where they intersect?
~~~~~~~~~~~~~~~~~~~~~~~~

The way which "josgarithmetic" offers to you is wrong and without hope to get the result.
It is because this person (I can not call him as a "tutor") is mathematically illiterate and has no any notion on
how to approach the problem correctly.

I will show you the way.

Introduce new variables u =   and  v = .

Then your system takes the form

2u -  5v =  5,    (1)
3u + 10v = 18.    (2)

Let us solve this system by the Elimination method. 
Multiply equation (1) by 2 (both sides) and then add to the equation (2).
You will get

4u + 3u = 10 + 18  --->  7u = 28  --->  u =  = 4.

Next, from (2)  10v = 18 - 3u = 18 - 3*4 = 6  --->  v =  =  = 0.6.

Now recall that u = .  Hence,  x =  = .

Similarly,  v = .  Hence,  y =  = .

The problem is solved.  The solution to the given/original system is found: x =,  y = .

The intersection point is  (x,y) = (,).
Solved.

It is a standard way solving such problems.
See the lessons
    - Solving systems of non-linear equations in two unknowns using the Cramer's rule
    - Solving systems of non-linear equations in three unknowns using Cramer's rule
in this site.

Also, you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this textbook under the section "Systems of equations that are not linear".


RELATED QUESTIONS

So the first line that should be plotted is y=3 and the second line is 4x+y=-5. I'm... (answered by ankor@dixie-net.com)
Find the equations of the tangents to the curve y = x^3 - x^2 - 2 at the point where x =... (answered by josgarithmetic)
x+3y=3 y=-1/3x+3 sketch graph i need to know the coordinates of each problem and... (answered by Alan3354)
Hello I really need help with this co ordinate question, it has been bugging me all... (answered by Alan3354)
Determine whether the pair of lines y = 2x + 1 and x - y = 5 are parallel or intersect.... (answered by fractalier,Fombitz)
Find the area enclosed between the curve y = x(x - 1)2 and the axis y = 0, establishing... (answered by Fombitz,richard1234)
find the point of intersections of... (answered by ikleyn)
solve y=-6x-5 y=-2x-1 where do these two lines intersect? your answer... (answered by josmiceli)
The tangent to the curve y = x^2 - 5x + 3 at a certain point is parallel to the line y =... (answered by josgarithmetic)