We are given a quadratic function $y = x^2 + (k+3)x + k+3$. We need to find the range of values for $k$ for which the quadratic function crosses the x-axis at two different points. This means that the quadratic equation $x^2 + (k+3)x + k+3 = 0$ has two distinct real roots.

AlgebraQuadratic EquationsDiscriminantInequalitiesRoots of Quadratic EquationsInterval Notation
2025/4/5

1. Problem Description

We are given a quadratic function y=x2+(k+3)x+k+3y = x^2 + (k+3)x + k+3. We need to find the range of values for kk for which the quadratic function crosses the x-axis at two different points. This means that the quadratic equation x2+(k+3)x+k+3=0x^2 + (k+3)x + k+3 = 0 has two distinct real roots.

2. Solution Steps

For a quadratic equation ax2+bx+c=0ax^2 + bx + c = 0 to have two distinct real roots, the discriminant must be greater than zero. The discriminant is given by D=b24acD = b^2 - 4ac.
In our case, a=1a=1, b=k+3b = k+3, and c=k+3c = k+3. So the discriminant is:
D=(k+3)24(1)(k+3)D = (k+3)^2 - 4(1)(k+3)
We want D>0D > 0, so we have:
(k+3)24(k+3)>0(k+3)^2 - 4(k+3) > 0
We can factor out (k+3)(k+3):
(k+3)[(k+3)4]>0(k+3)[(k+3) - 4] > 0
(k+3)(k1)>0(k+3)(k-1) > 0
Now we need to find the values of kk that satisfy this inequality. We can analyze the sign of the expression (k+3)(k1)(k+3)(k-1) by considering the intervals determined by the roots k=3k=-3 and k=1k=1.
Case 1: k<3k < -3. In this case, both (k+3)(k+3) and (k1)(k-1) are negative, so their product is positive.
Case 2: 3<k<1-3 < k < 1. In this case, (k+3)(k+3) is positive and (k1)(k-1) is negative, so their product is negative.
Case 3: k>1k > 1. In this case, both (k+3)(k+3) and (k1)(k-1) are positive, so their product is positive.
We want (k+3)(k1)>0(k+3)(k-1) > 0, so we need either k<3k < -3 or k>1k > 1.

3. Final Answer

The range of kk for which the quadratic function crosses the x-axis at two different points is k<3k < -3 or k>1k > 1. In interval notation, this is (,3)(1,)(-\infty, -3) \cup (1, \infty).

Related problems in "Algebra"

We are given that $(x+2)$ is a factor of the quadratic $x^2 + Px - 10$. We need to find the value of...

Quadratic EquationsFactor TheoremPolynomials
2025/4/10

The problem has two parts. First, we need to find the points of intersection of two given graphs, $y...

Quadratic EquationsSystems of EquationsLinear EquationsCurve IntersectionFunctions
2025/4/10

A woman received a 20% discount on a piece of cloth she purchased from a shop. She paid $525.00. We ...

PercentageLinear EquationsWord Problem
2025/4/10

The problem provides a table of $x$ and $y$ values for points on a linear graph. The goal is to find...

Linear EquationsSlopeCoordinate Geometry
2025/4/10

The problem asks which function results from applying a series of transformations to the base functi...

Function TransformationsLogarithmic FunctionsFunction Composition
2025/4/10

The problem states that the function $f(x) = log_{10}x$ has the point $(10, 1)$ on its graph. We ne...

LogarithmsFunction TransformationsCoordinate Geometry
2025/4/10

The problem asks to find the function that results from transforming $f(x) = \log_{10}x$ by a vertic...

Function TransformationsLogarithmic FunctionsTransformations of Graphs
2025/4/10

The problem asks to solve the logarithmic equation $\log_x 81 = 4$ for $x$.

LogarithmsEquationsExponentsSolving Equations
2025/4/10

The problem asks us to evaluate the logarithmic expression $\log_2 \sqrt[3]{64}$.

LogarithmsExponentsSimplification
2025/4/10

We need to determine which of the given statements about transformed logarithmic functions is true.

Logarithmic FunctionsTransformationsDomain and RangeAsymptotes
2025/4/10