Solve the system 2x+y=2,3x+2y=5 algebraically:
(1) Method I; substitution:
Solve the first equation for y : 2x+y=2
Subtract 2x from each side to get y=-2x+2
Now substitute this expression for y into the second equation:
3x+2y=5
3x+2(-2x+2)=5 solve for x:
3x-4x+4=5
-x=1 ==> x=-1
If x=-1 then y=-2(-1)+2=4
So the solution is x=-1,y=4 or the point (-1,4).
Check: 2(-1)+4=2 and 3(-1)+2(4)=5.
(2) Method II; elimination:
2x+y=2
3x+2y=5 Choose to eliminate y; multiply the first equation by -2 :
-4x-2y=-4
3x+2y=5 Now add the two equations together:
x+0=-1 ==> x=-1 and proceed as above.
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The solution to the system is (-1,4)
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