#How do I solve this?

14 messages · Page 1 of 1 (latest)

uneven hull
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The straight line y = kx + m passes through the point (4, 3) and intersects the line 3y + 5x - 15 = 0 at a point where both the x and y coordinates are positive numbers. Investigate what values of k are possible.

robust quailBOT
robust quailBOT
uneven hull
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Number 2. I think I should start converting 3y + 5x - 15 = 0 to y = 5 - (5/3)x but not sure what to do next

alpine lance
# uneven hull Number 2. I think I should start converting 3y + 5x - 15 = 0 to y = 5 - (5/3)x b...

That would be fine. If you have two line equations $y=l_1(x)$ and $y=l_2(x)$, then their graphs interect where their $y$ values become equal. That is, they interesct when $l_1(x)=l_2(x)$. From that, you'll need to alegbarically solve for $x$. That result will be the $x$-coordinate of the intersection. You can find the $y$ coordinate simply by plugging in your $x$ answer into either $l_1(x)$ or $l_2(x)$ (we set them equal, so it doesn't matter which you choose).

mortal sigilBOT
alpine lance
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You also know the line $y=kx+m$ passes through the point $(x=4, y=3)$, so $k$ and $m$ must also satisfy $3=k(4)+m$

mortal sigilBOT
uneven hull
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So what's the next step for a solution?

alpine lance
uneven hull
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Oh wait my bad. And what is done after that?

alpine lance
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You have solutions for x and y in terms of k. So you want to find which values of k will keep both positive.

uneven hull
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And do I just test my way to find that?