Q. \[ x^2 + x + 1 \]
Answer
To factor \(x^2+x+1\) over the integers, check the discriminant:
\[
\Delta = 1^2 – 4\cdot 1 \cdot 1 = 1-4=-3
\]
Since \(\Delta<0\), it does not factor into real (or integer) linear factors.
The exact factorization over the complex numbers is:
\[
x^2+x+1=\left(x-\frac{-1+i\sqrt{3}}{2}\right)\left(x-\frac{-1-i\sqrt{3}}{2}\right)
\]
Equivalently:
\[
x^2+x+1=\left(x+\frac{1+i\sqrt{3}}{2}\right)\left(x+\frac{1-i\sqrt{3}}{2}\right)
\]
Detailed Explanation
We are asked to work with the expression \(x^2 + x + 1\). Since the problem statement only shows this expression, there is no additional instruction (such as factoring, finding roots, simplifying, expanding, etc.). So the most helpful step-by-step response is to analyze common typical tasks for a quadratic like this: factoring, completing the square, and finding its discriminant/roots.
Step 1: Identify the type of expression
The expression \(x^2 + x + 1\) is a quadratic polynomial in \(x\), with coefficients:
\[
a = 1,\quad b = 1,\quad c = 1
\]
Step 2: Check whether it factors nicely over the integers
To factor a quadratic \(x^2 + x + 1\) over the integers, we look for two integers \(m\) and \(n\) such that:
\[
x^2 + x + 1 = (x + m)(x + n)
\]
This would require:
\[
m + n = 1,\quad mn = 1
\]
The integer pairs that satisfy \(mn = 1\) are \((m,n) = (1,1)\) or \((-1,-1)\).
If \((m,n) = (1,1)\), then \(m + n = 2\), not \(1\). If \((m,n) = (-1,-1)\), then \(m + n = -2\), not \(1\).
Therefore, it does not factor over the integers.
Step 3: Complete the square
Start with:
\[
x^2 + x + 1
\]
Group the first two terms and factor out the coefficient needed for completing the square:
\[
x^2 + x + 1 = \left(x^2 + x\right) + 1
\]
Take the coefficient of \(x\), which is \(1\), and halve it:
\[
\frac{1}{2}
\]
Square that value to get what we must add and subtract:
\[
\left(\frac{1}{2}\right)^2 = \frac{1}{4}
\]
Now rewrite \(x^2 + x + 1\) by adding and subtracting \(\frac{1}{4}\):
\[
x^2 + x + 1 = \left(x^2 + x + \frac{1}{4}\right) + 1 – \frac{1}{4}
\]
The expression \(x^2 + x + \frac{1}{4}\) is a perfect square:
\[
x^2 + x + \frac{1}{4} = \left(x + \frac{1}{2}\right)^2
\]
Also simplify \(1 – \frac{1}{4}\):
\[
1 – \frac{1}{4} = \frac{3}{4}
\]
So the completed-square form is:
\[
x^2 + x + 1 = \left(x + \frac{1}{2}\right)^2 + \frac{3}{4}
\]
Step 4: Interpret what this tells us (often used to check roots)
Because \(\left(x + \frac{1}{2}\right)^2 \ge 0\) for all real \(x\), we have:
\[
x^2 + x + 1 = \left(x + \frac{1}{2}\right)^2 + \frac{3}{4} \ge \frac{3}{4}
\]
This means \(x^2 + x + 1\) is always positive for real \(x\), so it has no real zeros.
Final result (useful simplified form)
\[
x^2 + x + 1 = \left(x + \frac{1}{2}\right)^2 + \frac{3}{4}
\]
Graph
Algebra FAQ
Factor \(x^2+x+1\).
Find the roots of \(x^2+x+1=0\).
What is the discriminant of \(x^2+x+1\)?
Complete the square for \(x^2+x+1\).
Determine whether \(x^2+x+1\) is always positive.
Find the minimum value of \(x^2+x+1\) on real numbers.
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