Max value of x+y (solving a linear system)?

AI Thread Summary
The problem involves finding the maximum value of x+y for a line passing through the point (3,4). The discussion reveals that the equations set up do not yield a maximum value, as both x and y can extend infinitely. Participants agree that the only logical conclusion is that the maximum value of x+y is infinity. Clarification is sought regarding the problem's parameters to ensure the question is correctly understood. The conclusion emphasizes that without constraints, x+y does not have a finite maximum.
holezch
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Homework Statement



A line passes through (3,4). What is the maximum value of x+y?

Homework Equations


y = mx + b

The Attempt at a Solution



So I set up a system of equations, m3+b =4; b = Y; mX + b = 0. Then I plugged my values for X and Y into m3+b = 4..
The weird thing is though... there is no maximum value of x+y?? It's just a line, x or y could go out further and further to infinity
How should I solve this? Thanks
 
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As you say, the only solution that makes sense here is "infinity". Are you sure you have the question right?
 
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Since ##px^9+q## is the factor, then ##x^9=\frac{-q}{p}## will be one of the roots. Let ##f(x)=27x^{18}+bx^9+70##, then: $$27\left(\frac{-q}{p}\right)^2+b\left(\frac{-q}{p}\right)+70=0$$ $$b=27 \frac{q}{p}+70 \frac{p}{q}$$ $$b=\frac{27q^2+70p^2}{pq}$$ From this expression, it looks like there is no greatest value of ##b## because increasing the value of ##p## and ##q## will also increase the value of ##b##. How to find the greatest value of ##b##? Thanks
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