Author Ari35g in Mathematics, 07.03.2018

How is 3x-y=8 and x+2y=5 solved by combination (addition)?????

Answered by christoph

First, multiply the first equation by 2.That turns the first equation into:6x - 2y = 18That way it can easily be added to the second equation:6x - 2y = 16x  + 2y = 5---------------7x = 21==========As you can see, the y disappeared, which was the objective of this operation.Now the equations can be solved easily:7x = 21x = 3Insert x=3 in the original equation:3*3 - y = 89 - y = 89 = 8 + yy = 1So the result is:x = 3y = 1

Answered by D3xt3R

Now we can multiply the first row by 2 and add to the second row.themnow we can replace the value in the first row.

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