Solving Quadratic Inequality: y = x² + 2x + 2 < 0

Quadratic Inequalities with No Solutions

Look at the following function:

y=x2+2x+2 y=x^2+2x+2

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

f(x)<0 f(x) < 0

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Look at the following function:

y=x2+2x+2 y=x^2+2x+2

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

f(x)<0 f(x) < 0

2

Step-by-step solution

To solve this problem, we need to rewrite the quadratic function y=x2+2x+2 y = x^2 + 2x + 2 into its vertex form. This process allows us to find the vertex and understand the behavior of the function.

First, we complete the square for the quadratic expression. Starting with:
y=x2+2x+2 y = x^2 + 2x + 2

We take the x x -terms x2+2x x^2 + 2x and complete the square as follows:

  • Take half of the coefficient of x x , which is 2, resulting in 1.
  • Square this value to get 1.
  • Add and subtract this square inside the equation to maintain equality.

Therefore, x2+2x+11+2 x^2 + 2x + 1 - 1 + 2 can be rewritten as:
y=(x+1)2+1 y = (x+1)^2 + 1

Now, the function is in the form y=(x+1)2+1 y = (x+1)^2 + 1 , which shows the vertex at (1,1) (-1, 1) . The vertex is the minimum point because the parabola opens upwards (as the coefficient of x2 x^2 is positive).

This vertex indicates that the minimum value of y y is 1, which means the function never reaches below zero. As a result, the function never assumes negative values.

Based on this analysis, we conclude that the function has no negative values.

The correct answer is therefore: The function has no negative values.

3

Final Answer

The function has no negative values.

Key Points to Remember

Essential concepts to master this topic
  • Vertex Form: Complete the square to find y=(x+1)2+1 y = (x+1)^2 + 1
  • Technique: Half of coefficient 2 gives 1, square it: x2+2x+1 x^2 + 2x + 1
  • Check: Minimum value at vertex (-1, 1) is positive, so no negative values ✓

Common Mistakes

Avoid these frequent errors
  • Trying to solve x² + 2x + 2 = 0 using factoring or quadratic formula
    Don't attempt to find x-intercepts when the parabola doesn't cross the x-axis = no real solutions! This leads to confusion about negative discriminants. Always complete the square to find the vertex form and analyze the minimum/maximum value.

Practice Quiz

Test your knowledge with interactive questions

The graph of the function below does not intersect the \( x \)-axis.

The parabola's vertex is marked A.

Find all values of \( x \) where
\( f\left(x\right) > 0 \).

AAAX

FAQ

Everything you need to know about this question

Why can't I just factor x² + 2x + 2?

+

This quadratic doesn't factor nicely over real numbers! The discriminant b24ac=48=4 b^2 - 4ac = 4 - 8 = -4 is negative, meaning no real roots exist.

How do I know the parabola opens upward?

+

Look at the coefficient of x2 x^2 ! Since it's positive (+1), the parabola opens upward like a smile. This means the vertex is the minimum point.

What does 'no negative values' actually mean?

+

It means the function f(x)<0 f(x) < 0 has no solutions. The smallest value this function can take is 1 (at the vertex), which is always positive.

Can I use the quadratic formula to check this?

+

Yes! For x2+2x+2=0 x^2 + 2x + 2 = 0 , the discriminant is 48=4<0 4 - 8 = -4 < 0 . A negative discriminant confirms no real solutions exist.

How do I complete the square step by step?

+

Take x2+2x x^2 + 2x :

  • Half the coefficient of x: 2 ÷ 2 = 1
  • Square it: 1² = 1
  • Add and subtract: x2+2x+11 x^2 + 2x + 1 - 1
  • Factor: (x+1)21 (x+1)^2 - 1

🌟 Unlock Your Math Potential

Get unlimited access to all 18 The Quadratic Function questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime

More Questions

Click on any question to see the complete solution with step-by-step explanations