y =6x^2 - 9x + c, y = 5x^2 - 3x
Let c be a real number, and consider the system of quadratic equations
For which values of does this system have:
(a) Exactly one real solution
(b) More than one real solution?
(c) No real solutions?
We can analyze the system of quadratic equations to determine the number of real solutions for different values of c. Here's how:
Analyzing the Discriminant:
The discriminant of a quadratic equation determines the nature of its roots (solutions). It is denoted by the symbol b2−4ac. In this case, considering the first equation (y = 6x^2 - 9x + c):
a = 6
b = -9
c (variable)
The discriminant (d) for the first equation is:
d = (-9)^2 - 4 * 6 * c
The number of real solutions depends on the value of the discriminant:
d > 0: Two real and distinct solutions (roots)
d = 0: One repeated real solution (root)
d < 0: No real solutions (complex roots)
Relating Discriminant to c:
We want to find the values of c that correspond to each case.
(a) Exactly one real solution:
For exactly one real solution (repeated root), the discriminant needs to be zero.
Therefore, we need to solve:
0 = (-9)^2 - 4 * 6 * c
This simplifies to:
c = \frac{81}{24} = \dfrac{7}{2}
(b) More than one real solution:
For more than one real solution (distinct roots), the discriminant needs to be positive.
Therefore, we need to solve:
0 < (-9)^2 - 4 * 6 * c
This simplifies to:
c < \dfrac{81}{24} = \dfrac{7}{2}
(c) No real solutions:
For no real solutions (complex roots), the discriminant needs to be negative.
Therefore, we need to solve:
0 > (-9)^2 - 4 * 6 * c
This simplifies to:
c > \dfrac{81}{24} = \dfrac{7}{2}
Summary:
(a) Exactly one real solution: c = dfrac{7}{2}
(b) More than one real solution: c < dfrac{7}{2}
(c) No real solutions: c > dfrac{7}{2}