What Values of K Make the Intersection of Two Graphs Positive?

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SUMMARY

The discussion focuses on determining the values of 'k' for which the line represented by the equation y = kx + 3 intersects the parabola y = x^2 + 8x at two distinct points. Participants emphasize the importance of the discriminant from the quadratic equation formed by setting the two equations equal. The discriminant, given by (k - 8)^2 + 12, must be greater than zero for two distinct intersections to occur. The conclusion is that for any value of 'k', the intersection will always yield two distinct points, as the discriminant is always positive.

PREREQUISITES
  • Understanding of quadratic equations and their properties
  • Familiarity with the quadratic formula
  • Knowledge of discriminants and their role in determining the nature of roots
  • Ability to manipulate algebraic expressions and inequalities
NEXT STEPS
  • Study the properties of quadratic functions and their graphs
  • Learn how to apply the quadratic formula in various contexts
  • Explore the concept of discriminants in depth, particularly in relation to real solutions
  • Investigate the method of completing the square for quadratic equations
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Mathematics students, educators, and anyone interested in algebraic functions and their intersections, particularly those studying quadratic equations and their applications in graphing.

  • #31
Try completing the square: x^2- 16k+ 76= (x- ?)^2+ ?. Now, what values of k make that positive?
 
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  • #32
HallsofIvy said:
Try completing the square: x^2- 16k+ 76= (x- ?)^2+ ?. Now, what values of k make that positive?
Been there and done that. See post #27.
 

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