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how do you solve this simultaneous equation?

5x-19=2y
2x-y/3=2
Reply 1
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11234
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Original post by p29
5x-19=2y
2x-y/3=2


times the second equation by 5/2 then subtract and solve
Reply 2
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p29
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Original post by 11234
times the second equation by 5/2 then subtract and solve

how do you subtract with the fraction?
Reply 3
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11234
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Original post by p29
how do you subtract with the fraction?

subtract second equation from first so the 5x cancels out
Reply 4
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p29
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Original post by 11234
subtract second equation from first so the 5x cancels out


im left with -35=4y
-5y/3=10
how do i subtract these?
Reply 5
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p29
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ffs
Reply 6
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11234
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Original post by p29
im left with -35=4y
-5y/3=10
how do i subtract these?


1) 5x-19=2y
2)5x-5y/6=5

==>5y/6-19=2y-5

Finisih it off
Original post by p29
5x-19=2y
2x-y/3=2


Here are our two equations.

5x - 19 = 2y (1)
2x - y/3 = 2 (2)

Multiply equation (2) by 3 to get rid of the fraction.

5x + 2y = 19 (1)
6x - y = 6 (2)

Rearrange to get y on its own.

y = 6x - 6

Therefore, by substituting our new value for y into equation (1),

5x + 2(6x - 6) = 19

Simplify and rearrange,

5x + 12x - 12 = 19
17x = 31
x = 31/17

If x = 31/17, substitute this into equation (2) to find y.

6(31/17) - y = 6

Simplify and rearrange,

y = 6(31/17) - 6 [I don't have a calculator so you'll have to do the maths yourself]

And therein you have your two solutions.
Reply 8
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11234
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Original post by jake4198
Here are our two equations.

5x - 19 = 2y (1)
2x - y/3 = 2 (2)

Multiply equation (2) by 3 to get rid of the fraction.

5x + 2y = 19 (1)
6x - y = 6 (2)

Rearrange to get y on its own.

y = 6x - 6

Therefore, by substituting our new value for y into equation (1),

5x + 2(6x - 6) = 19

Simplify and rearrange,

5x + 12x - 12 = 19
17x = 31
x = 31/17

If x = 31/17, substitute this into equation (2) to find y.

6(31/17) - y = 6

Simplify and rearrange,

y = 6(31/17) - 6 [I don't have a calculator so you'll have to do the maths yourself]

And therein you have your two solutions.

I got y=-12 and x=-1. Not sure your values satisfy 1
Reply 9
Avatar for MartyO
MartyO
7
I made this animated PowerPoint a while back explaining techniques to solve simultaneous equations, if it helps:
https://www.dropbox.com/s/ono0irvomyy07sp/Solving%20Systems%20Of%20Linear%20Equations.pptx?dl=0
Original post by 11234
I got y=-12 and x=-1. Not sure your values satisfy 1


Do the math by using the calculated values. If you get the equal value on both sides in one of the equations, the calculated values are right.

For me the calculation steps of jake4198 look good.
Reply 11
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11234
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Original post by Kallisto
Do the math by using the calculated values. If you get the equal value on both sides in one of the equations, the calculated values are right.

For me the calculation steps of jake4198 look good.


for jake x=31/17 y=6(31/17)-6=84/17
5(31/17)-19=-168/17 not 168/17(2x84/17)
Original post by jake4198
Here are our two equations.

5x - 19 = 2y (1)
2x - y/3 = 2 (2)

Multiply equation (2) by 3 to get rid of the fraction.

5x + 2y = 19 (1)
6x - y = 6 (2)

Rearrange to get y on its own.

y = 6x - 6

Therefore, by substituting our new value for y into equation (1),

5x + 2(6x - 6) = 19

Simplify and rearrange,

5x + 12x - 12 = 19
17x = 31
x = 31/17

If x = 31/17, substitute this into equation (2) to find y.

6(31/17) - y = 6

Simplify and rearrange,

y = 6(31/17) - 6 [I don't have a calculator so you'll have to do the maths yourself]

And therein you have your two solutions.


The emboldened steps are incorrect. It should be 5x-2y=19 and 5x - 2(6x-6)=19
Original post by 11234
for jake x=31/17 y=6(31/17)-6=84/17
5(31/17)-19=-168/17 not 168/17(2x84/17)


You said that x = -1 and y = -12 are the solutions, right? let us see, if it works in equation 5x-19 = 2y:
*
5*(-1) - 19 = 2*(-12) *
-24 = -24 *

As you can see, it works! your solutions, calculated by jake4198 are right. By the way the misplaced stars(*) are a goddamn ****ing glitch!*
(edited 7 years ago)
Reply 14
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p29
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Original post by MartyO
I made this animated PowerPoint a while back explaining techniques to solve simultaneous equations, if it helps:
https://www.dropbox.com/s/ono0irvomyy07sp/Solving%20Systems%20Of%20Linear%20Equations.pptx?dl=0

thank you

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