Equation of a line finding x and y intercepts

Question

Find the equation of the line through the y-intercept of y=x^4 - 7 x^ 5  - 9 + 8 x^ 2 and the x-intercept of y=11 x - 8.

Answer 1

Hi Brooklyn:

 

Set your x's to zero when finding the y-intercept, and set your y's to zero when finding the x-intercept.  The reason for this is because your equation of a line will always have x = 0 when it intercepts/crosses the y-axis, and will always have y = 0 when it intercepts.crosses the x-axis.

 

So, for the first equation set the x's to zero, and you are left with y = -9, and for the second equation set the y's to zero, and you are left with x = 8/11.  Those are your equations of lines of intercepts!

 

Jason

 

 

Answer 2

To find the y intercept of the first equation you just plug in x= 0 and solve. You get y = -9. That is the equation of the line of the y intercept.  

 

For the x intercept of the second equation, you set y=0 and solve, and you get 11x=8  so x = 8/11, and that is the equation of the line through the x intercept.

 

I'm not sure if this is what you're asking but if you want the equation of the line that passes through those two points, you first find the slope using your two coordinate points: (0,-9), and (8/11,0). So your slope is deltay/deltax = -9/-(8/11) = 12.375.

 

We already know the y intercept is -9.

 

So the equation of our line in the form of y=mx + b , we have y = 12.375X - 9