How do you solve $3x+y=3$ and $2y=-6x+6$ ?

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Answer 1 · 2016-07-04T18:33:12

This is an identity, it will work for any values of x and y.

There are several methods for solving simultaneous equations, but in this case I like the idea that $y = y$

If we can get both equations written in terms of $y$ , then we can equate them. We have:
$3x + y = 3 " and "2y = -6x +6$

$:." "y = 3-3x " " y= -3x +3$

$y = y rArr " "3-3x = -3x +3$

This simplifies to $" " 0 = 0 " but there is no " x$ ?

This is an example of an identity which means that there is no single solution and the equations will work for all values of x and y.

How do you solve 3x+y=33x+y=3 and 2y=-6x+62y=-6x+6?