Question 741771
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For the following system, if you isolated x in the first equation to use the Substitution Method, 
what expression would you substitute into the second equation?

-x + 2y = 9
4x + 5y = 9
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<pre>
I isolate 'x' in the first equation by moving 'x' to the right side (with changing its sign)
and moving '9' to the left side (with changing its sign)

    2y - 9 = x.


Then precisely this expression I will substitute into the second equation, replacing 'x' there
with 2y-9.
</pre>

Thus I answered your question.