question

BK94

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Oct 17, 2010
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I was wondering how do yo u find the x and y intercept of y=2x+4?
 

mmm4444bot

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x-intercepts are points that take this form: (x, 0).

I mean, all x-intercepts occur where y = 0.

Substitute 0 for y in your equation, and solve for x.

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y-intercepts are points that take this form: (0, y).

I mean, all y-intercepts occur where x = 0.

Substitute 0 for x in your equation, and solve for y.

Alternatively, you could recognize that the given equation is written in the Slope-Intercept form of a line. You can see the y-intercept, by inspection.

 

BK94

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Oct 17, 2010
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10
im still lost....
 

mmm4444bot

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The instruction "substitute 0 for x in the equation" means to write this:

y = 2(0) + 4

Now, do the math.

y = 0 + 4

y = 4

The y-intercept is 4.

That means the line passes through the point (0, 4).

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Likewise, the x-intercept is the point where the line crosses the x-axis. The y-coordinate is zero, there. We substitute zero for y.

0 = 2x + 4

Solve for x means to get x by itself on one side.

Subtract 4 from both sides, to first isolate the term containing x.

0 - 4 = 2x + 4 - 4

Do the math.

-4 = 2x

Isolate x by dividing both sides by 2

-4/2 = 2x/2

Do the math

-2 = x

The x-intercept is -2.

That means the line passes through the point (-2, 0).

 

BK94

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Oct 17, 2010
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10
ok i get it now thanks a lot.
 
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