The discriminant for the equation 2 x 2 − 9 x + 2 = − 1 is calculated to be 57, which is greater than 0. This indicates that there are two distinct real roots for the equation. Therefore, the correct option is C: The discriminant is greater than 0, so there are two real roots.
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To determine which statement about the equation 2 x 2 − 9 x + 2 = − 1 is true, we first need to set it to zero by moving all terms to one side:
2 x 2 − 9 x + 2 + 1 = 0
This simplifies to:
2 x 2 − 9 x + 3 = 0
Next, we calculate the discriminant of this quadratic equation. The discriminant D is calculated using the formula:
D = b 2 − 4 a c
For our equation, a = 2 , b = − 9 , and c = 3 . Substituting these values in, we get:
D = ( − 9 ) 2 − 4 × 2 × 3
Calculate each part:
( − 9 ) 2 = 81
4 × 2 × 3 = 24
So the discriminant is:
D = 81 − 24 = 57
Since the discriminant D = 57 is greater than 0, it indicates that there are two distinct real roots for the quadratic equation.
Therefore, the correct statement is:
C. The discriminant is greater than 0, so there are two real roots.