Solve the Quadratic Inequality: 2x² - 12x + 18 < 0

Question

Solve the following equation:

2x^2-12x+18<0

Video Solution

Step-by-Step Solution

To solve this inequality 2x212x+18<0 2x^2 - 12x + 18 < 0 , we perform the following steps:

  • Step 1: Compute the discriminant. Here, a=2 a = 2 , b=12 b = -12 , and c=18 c = 18 . Plug these into the discriminant formula:

Δ=b24ac=(12)24×2×18=144144=0\Delta = b^2 - 4ac = (-12)^2 - 4 \times 2 \times 18 = 144 - 144 = 0

  • Step 2: Interpret Δ=0\Delta = 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 2x212x+18<0 2x^2 - 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 x for which the quadratic expression 2x212x+18<0 2x^2 - 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.

Answer

The function is negative for all values of x.


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