simultaneous equations

2x + y = 7          ...(1)

  x + y = 4          ...(2)

 

Subtract (2) from (1) term by term

2x - x + y - y = 7 - 4

 

Simplify

x = 3

 

Put this back into (2

3 + y = 4

 

Subtract 3 from both sides

y = 1

 

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