System of equations x+y = 7 3x-y=1

We can solve this system of equations by reduction method.
  x+y=7
3x-y=1
-
  4x=8    ⇒x=8/4=2
-3(x+y=7)
   3x-y=1
-
       -4y=-20  ⇒y=-20/-4=5
Answer: x=2, y=5
we can solve this systeme by susbtitution method.
x+y=7  ⇒ x=7-y
3x-y=1
3(7-y)-y=1
21-3y-y=1
-4y=1-21
-4y=-20
y=-20/-4=5
x=7-y=7-5=2
Answer: x=2, y=5.
We can solve this systemen of equation by equalization method.
x+y=7       ⇒y=7-x
3x-y=1      ⇒y=3x-1
7-x=3x-1
-x-3x=-1-7
-4x=-8
x=-8/-4=2
y=7-x
y=7-2=5
Answer: x=2, y=5


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