Final answer:
The product of roots of a quadratic equation is given by -c/a, and the sum of roots is given by -b/a. For real and unequal roots, b² - 4ac should be greater than zero. When the discriminant is zero, the quadratic equation has real and equal roots.
Step-by-step explanation:
The product of the roots (mn) of a quadratic equation ax² + bx + c = 0 is mn = -c/a. For the given quadratic equation px² - 6x + 9 = 0, the sum of the roots (a + b) is a + b = -(-6)/p = 6/p. To find p² + q², we use the identity p² + q² = (p + q)² - 2pq where p + q = -b/a and pq = c/a, thus p² + q² = (b² - 4ac)/a².
For the equation 2x² - 5x + k = 0, the sum of roots (α+β) is α+β = -(-5)/2 = 5/2. An equation with roots x = 2 and x = -3 translates to (x - 2)(x + 3) = 0 or 2x² - 5x - 6 = 0. If b² - 4ac > 0, the quadratic equation has real and unequal roots.
If the discriminant (Δ) is zero, the roots are real and equal. The sum of the roots (α+β) of ax² + bx + c = 0 is α+β = -b/a. When the equation has no real roots, it means b² - 4ac < 0. The product of the roots (α •β) in terms of coefficients a, b, c is α •β = c/a.