How do you solve this system of equations: −x−2y=−4and2x−y=3?

1 Answer
Alok Shukla
Dec 14, 2017

x=2,y=1

Explanation:

Algebra

2x−y=3

4x−2y=6 -- (i)

−x−2y=−4 -- (ii)

equation i minus equation ii,

(4x−2y)−(−x−2y)=6−(−4)

4x−2y+x+2y=10

5x=10

x=2

Putting it in equation (i),

4(2)−2y=6

4−y=3

y=1

So, the answer is x=2,y=1.

Geometry

2x−y=3⇒y=2x−3

−x−2y=−4⇒y=−x2+2

Plotting these lines,

graph{(2x-y-3)(x+2y-4)=0}

These cross each other at (2,1) so the solution to these equations will be x=2,y=1.

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