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 Posted: Sun Oct 10, 2010 3:34 pm
So I have problems like this:
Which ordered pair is a solution to this equation?
y = 2x + 1
And it's been awhile since I've done these, so I can't remember what to do to get the ordered pair. Like putting the 2 on the x part of the graph type thing, or whatever it is. I remember being able to do these, I just can't remember how. D: So any help would be appreciated. 3nodding
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Posted: Sun Oct 10, 2010 6:53 pm
so all you have to do for a problem like this is pick a value of x that you would like to use, then plug it in for x, and see what value of y pops out, and that will be your ordered pair. Here are some examples
pick 0 to be x
x = 0
so plug in 0 into the equation where you see x
y = 2*x +3
y = 2*0 +3
so then you just do the math
2*0=0 implies...
y = 0 +3
y= 3
so your value for x was 0 and your resulting y was 3 then you put your ordered pair in the form
(x,y)
where again x=0 and y=3. So your answer should be
(0,3)
ok lets try a few more except at a faster pace, see if you can follow the steps, let x=-1
y= 2x +3
y= 2*-1 +1
y=-2+1
y=-1
(x,y) = (-1,-1)
let x=1
y=2*1+3
y=2+3
y=5
(1,5)
the important thing to remember is that here since we have 2 variables now, you can pick any value of x you'd like and it will give you a value of y.
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Posted: Sun Oct 10, 2010 9:49 pm
A follow up question to this might be something to the effect of
does the ordered pair (2,3) satisfy the equation
here you just remember that x=2 and y=3 then ask the question "Does y equal 2x+3 when x=2 and y=3?" Just find out by plugging them back into the equation
y = 2x + 3
3= 2*2+3
3= 4 +3
3 = 7 this is /not/ true, so the ordered pair does not satisfy the equation.
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