- Thread starter frctl
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What are your thoughts?40x_{1}+ 30x_{2}= 24

20x_{1}+ 15x_{2}= -14

Where are you stuck?

You have 100+ posts -- you should know that you need to show us your efforts before we put in our efforts to help you solve your problem.

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Go ahead and try and show your work.I think I must solve by back substitution but I think I am must reduce first

We will start discussion from there.

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What method you are trying to apply? - matrix? substitution? elimination? something else?I don't see any common factor, can I instead add both equations together?

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So use one of those and show us the work!I can use any, I am asked simply to solve

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Try again!40x_{1}+ 30x_{2}= 24

20x_{1}+ 15x_{2}= -14

Multiply equation 2 by 2

40x_{1}+ 30x_{2}= 24

40x_{1}+ 30x_{2}= -28

Adding both equations gives me -4................................Incorrect

However, addition will not guide you towards a valid conclusion.

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Did you figure out:What can I do in the place?

What mistake did you make in your response #9?

You are adding two sets of equations - the result should an equation (not a number).

First correct your mistake - then we will discuss "what you can do in its place".

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Next - what operation did you conduct?40x_{1}+ 30x_{2}= 24

20x_{1}+ 15x_{2}= -14

Multiply equation 2 by 2

40x_{1}+ 30x_{2}= 24

40x_{1}+ 30x_{2}= -28

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You still did not fix your mistake in your response #9!I isolated x_{1}

x_{1}= (-30x_{2}+24)/40

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Redo your response #9 with "corrected" steps.I can't edit this response anymore.

Is there another mistake?

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What part of my statement you do not understand?I don't understand what do you mean

While writing response #9 - you conducted some mathematical steps and you made a conclusion (which was incorrect).

I would like for you to "find" your mistake and correct your conclusion (in a new post - since you cannot edit it).