SOLUTION: . A quadratic function is defined by f (x) = −3.7x^2 + 6.8x + 4.3 . A linear function is defined by g(x) = −0.5x + k a) Determine the value of k so that the line inter

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: . A quadratic function is defined by f (x) = −3.7x^2 + 6.8x + 4.3 . A linear function is defined by g(x) = −0.5x + k a) Determine the value of k so that the line inter      Log On


   



Question 1090537: . A quadratic function is defined by f (x) = −3.7x^2 + 6.8x + 4.3 . A linear function is defined by g(x) = −0.5x + k
a) Determine the value of k so that the line intersects the parabola at exactly one point. Write your answer to the nearest hundredth.
b) Determine the values of k so that the line intersects the parabola at two points.
c) Determine the values of k so that the line never intersects the parabola.

Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29=g%28x%29
-3.7x%5E2%2B6.8x%2B4.3=-0.5x%2Bk
3.7x%5E2-6.8x-4.3=0.5x-k
3.7x%5E2-7.3x-4.3%2Bk=0

DISCRIMINANT, D=%28-7.3%29%5E2-4%2A3.7%2A%28k-4.3%29
D=53.29-14.8k%2B63.64
D=116.93-14.8k

A) One intersection
116.93-14.8k=0

B) Two intersections
116.93-14.8k%3E0


C) No intersections
116.93-14.8k%3C0

Solve for k in each case.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
. A quadratic function is defined by f (x) = −3.7x^2 + 6.8x + 4.3 . A linear function is defined by g(x) = −0.5x + k
a) Determine the value of k so that the line intersects the parabola at exactly one point. Write your answer to the nearest hundredth.
b) Determine the values of k so that the line intersects the parabola at two points.
c) Determine the values of k so that the line never intersects the parabola.
Hint: If a line intersects a parabola at EXACTLY one (1) point, that point WILL BE the VERTEX of the parabola. 
Therefore, find the vertex of the parabola by using the formula for the x-coordinate of the vertex of a parabola: x+=+-+b%2F%282a%29.
Then substitute this x-value into the PARABOLIC equation to get the corresponding y-coordinate of the vertex.
Substitute these PARABOLIC vertex-values: (h, k) as (x, y) into the linear function to get the value of k.