graphing linear equations with just one intercept

cougar77d

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can anyone help me with my homework?
i need to graph linear equations with just one intercept. like; -4x+5y=o, and y=2x
can anyone help me?
 

o_O

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What do you mean by "with just one intercept"?

Are you graphing those individually? Easiest way would be to find the x-intercept (by solving for x when y = 0) and the y-intercept (by solving for y when x = 0) and connect them with a line, extending both ways.
 

cougar77d

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one intercept as in, through the zero. my teacher said to use whatever numbers i wanted to but i still dont get it.
 

o_O

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Oh sorry, didn't pay attention to your equations. Both of them only "just have one intercept." So just pick any other point and connect the origin (0,0) with the other point.
 

cougar77d

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ok. but how do i do that using whatevr numbers i want?
 

o_O

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What do you mean? Lets say for the equation -4x + 5y = 0. Choose any number for x and solve for y to get its corresponding value. This gives you another set of numbers, a coordinate point, which satisfies the equation. Then, connect the two points with a line.
 

cougar77d

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so multiply -4 by whatever number i choose then add/subtract it on both sides of the =sign, then divide that by 5?
 

o_O

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Yep. Solving for y. It's an equation. If you already know the value of x (which you chose) then you just use simple algebra to find the corresponding y value.
 

cougar77d

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so lets say i chose 20 to represent x, the number i get out of the 20 over 5 then represent y?
 

cougar77d

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could i use the y=mx+b formula for this?
 

o_O

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Sure but it's essentially the same thing. You're plugging in x = 20 to get some value for y. So if you chose x = 20:

-4(20) + 5y = 0
-80 + 5y = 0
etc. etc.

Usually, you use smaller x values so that your axes are easier to deal with. So maybe x = 5?

Also, if you really want you could put it into the y = mx + b form.
-4x + 5y = 0
5y = -4x
y = -4x/5

Same result either way.
 

cougar77d

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sorry. i didnt mean 4(20), i just meant the answer of 20. ok thank you.
 
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