Solve the following equation:
2x^2-12x+18<0
To solve this inequality 2x2−12x+18<0, we perform the following steps:
- Step 1: Compute the discriminant. Here, a=2, b=−12, and c=18. Plug these into the discriminant formula:
Δ=b2−4ac=(−12)2−4×2×18=144−144=0
- Step 2: Interpret Δ=0. A discriminant of zero means the quadratic equation has one repeated real root. The graph of the quadratic is a parabola that touches the x-axis at a single point, at the vertex.
- Step 3: Since the parabola described by the quadratic has no interval crossing the x-axis (it only touches it at a point), the inequality 2x2−12x+18<0 has no solutions. A parabola touching the x-axis at a single vertex point does not lie below the x-axis.
Therefore, there are no values of x for which the quadratic expression 2x2−12x+18<0. The function does not attain negative values.
The correct answer to the multiple-choice question is therefore:
The function is negative for all values of x.
The function is negative for all values of x.