Rule:
Ax² + Bx + C = 0
1. Substitute A, B, and C in the discriminant formula
Discriminant = B² - 4AC
2. If the discriminant is a positive number then the equation
has two real solutions.
3. If the discriminant is a negative number then the equation
has two conjugate imaginary solutions.
4. If the discriminant is zero then the equation
has one real solution.
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2x² + x + 28 = 0
A = 2, B = 1, C = 28
Substitute A=2, B=1, and C=28 in the discriminant formula
Discriminant = B² - 4AC
Discriminant = 1² - 4(2)(28)
Discriminant = 1 - 224
Discriminant = -223
-223 is a negative number, so the equation has two
conjugate imaginary solutions.
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6x² - 2x + 5 = 0
A = 6, B = -2, C = 5
Substitute A=6, B=-2, and C=5 in the discriminant formula
Discriminant = B² - 4AC
Discriminant = (-2)² - 4(6)(5)
Discriminant = 4 - 120
Discriminant = -116
-116 is a negative number, so the equation has two
conjugate imaginary solutions.
Edwin