Determine X for y=x²-4x+5 When f(x) < 0

Question

Look at the function below:

y=x24x+5 y=x^2-4x+5

Determine for which values of x x the following is true:

f(x) < 0

Step-by-Step Solution

To solve this problem, we first consider the function y=x24x+5 y = x^2 - 4x + 5 . This is a quadratic function, and we can analyze the parabola it represents.

The standard form of a quadratic function is y=ax2+bx+c y = ax^2 + bx + c , where in our case a=1 a = 1 , b=4 b = -4 , and c=5 c = 5 .

To determine if the function has any negative values, we first find the vertex of the parabola. The vertex form of a quadratic function is determined by:

  • The x x -coordinate of the vertex is given by x=b2a x = -\frac{b}{2a} .

Plugging in our values:

x=42×1=42=2 x = -\frac{-4}{2 \times 1} = \frac{4}{2} = 2 .

The y y -coordinate of the vertex can be found by substituting x=2 x = 2 back into the equation:

y=(2)24(2)+5=48+5=1 y = (2)^2 - 4(2) + 5 = 4 - 8 + 5 = 1 .

The vertex of the parabola is (2,1) (2, 1) , which means the minimum point of the parabola is above the x-axis at y=1 y = 1 .

Next, we assess whether there are any real roots by finding the discriminant Δ \Delta :

Δ=b24ac=(4)24×1×5=1620=4 \Delta = b^2 - 4ac = (-4)^2 - 4 \times 1 \times 5 = 16 - 20 = -4 .

Since the discriminant is negative (Δ<0 \Delta < 0 ), this indicates the parabola does not intersect the x-axis at any real point. Therefore, it never dips below the x-axis.

Given that the vertex is above the x-axis and the discriminant is negative, the quadratic function y=x24x+5 y = x^2 - 4x + 5 is never negative for any real x x .

The function has no negative values.

Answer

The function has no negative values.