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

1 Answer
Jul 4, 2016

Answer:

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

Explanation:

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.