i need a lot of help i have a couple different questions.

Question

anonymous · Answer

For the following system, if you isolated y in the first equation to use the Substitution Method, what expression would you substitute into the second equation?

4x − y = 8
2x + 3y = 9

 8 − 4x

 8 + 4x

 −8 + 4x

 −8 − 4x

terenzreignz · Answer

First... isolate y in the first equation.  Can you do that?

anonymous · Answer

so add negative 4x by 8

terenzreignz · Answer

Sure... you could do that... you should get
4x - y - 4x = 8 - 4x

And then?

anonymous · Answer

Remember the y coefficient

anonymous · Answer

you subtract 8 by 4x and get 4x then you divide 4x by 4x right?

anonymous · Answer

Seriously. Don't forget it

terenzreignz · Answer

You cannot subtract 4x from 8 and get 4x...
because they are not similar terms... 8 has not x attached to it.

anonymous · Answer

i do not understand

anonymous · Answer

subtract 4x from 8; it will be left as such

terenzreignz · Answer

$$\huge 8 - 4x = 4x  \color{red}\times$$$$\huge 8\color{blue}x-4x = 4x \color{green} {\checkmark}$$

anonymous · Answer

remember that this is equal to -y.
You're looking for y, right? not -y?

terenzreignz · Answer

You may only subtract terms that have the same variables attached to them-
8 - 4x
there is no x attached to 8, hence you may not subtract 4x from it and get a result 4x...

anonymous · Answer

4x - y = 8 : -y = 8 - 4x : y = -8 + 4x