4x+y=4 8x+5y=8

4x + y = 4   ...(1)

8x + 5y = 8  ...(2)

 

Multiply each term in (1) by 2

8x + 2y = 8  ...(3)

 

Subtract (3) term by term from (2):

8x - 8x  +  5y - 2y = 8 - 8

3y = 0

y = 0

 

 Put this back into (1)

4x + 0 = 4

 

x = 1

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