How do you solve the following linear system: #3x - 6y = 9 , y = 1/2x - 3/2 #?

1 Answer
Veddesh #phi#
Feb 7, 2016

Solve by substitution:

#3x - 6y = 9 , y = 1/2x - 3/2 #

In the second equation the value of #y# can be substituted to the first equation:

#rarr3x-6(1/2x-3/2)=9#

Use distributive property (#a(b+c)=ab+ac#):

#rarr3x-(3x-9)=9#

#rarr3x-3x+9=9#

#rarr9=9#

So,if you see a equation ending like this,they mean that the value is possible for all real numbers.The value of #x# is all the real numbers in mathematics.

Now we know that #x# corresponds to all real numbers.So, #y# is as same as the second equation:

#=>y=1/2x-3/2#

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