Q. \(\,x^2 – x – 6\,\)
Answer
\(x^2-x-6\) factors as \((x-3)(x+2)\).
Set each factor to zero:
\(x-3=0 \Rightarrow x=3\), and \(x+2=0 \Rightarrow x=-2\).
Final result: \(x=3\) or \(x=-2\).
Detailed Explanation
We want to solve the expression \(x^2 – x – 6\). A common goal for a quadratic expression like this is to factor it (and we can then find its zeros if needed).
Step 1: Identify the quadratic form
The expression is
\[x^2 – x – 6\]
This matches the general quadratic form \(ax^2 + bx + c\) where:
\(a = 1\), \(b = -1\), and \(c = -6\).
Step 2: Factor the quadratic
We look for two numbers that:
- Multiply to \(ac = 1 \cdot (-6) = -6\).
- Add to \(b = -1\).
The pair of integers that works is \(-3\) and \(2\), because:
\((-3)(2) = -6\)
\((-3) + 2 = -1\)
Step 3: Rewrite using those two numbers
Split the middle term \(-x\) using \(-3\) and \(2\):
\[x^2 – x – 6 = x^2 – 3x + 2x – 6\]
Step 4: Factor by grouping
Group the terms:
\[x^2 – 3x + 2x – 6 = (x^2 – 3x) + (2x – 6)\]
Now factor each group:
\[x^2 – 3x = x(x – 3)\]
\[2x – 6 = 2(x – 3)\]
Step 5: Combine the common factor
Both groups contain \((x – 3)\), so factor it out:
\[x(x – 3) + 2(x – 3) = (x + 2)(x – 3)\]
Final result (factored form)
\[x^2 – x – 6 = (x + 2)(x – 3)\]
Graph
Algebra FAQ
Factor \(x^2-x-6\) into linear factors.
Solve \(x^2-x-6=0\) using factoring.
Find the roots of \(x^2-x-6\) using the quadratic formula.
Complete the square for \(x^2-x-6\).
What are the \(x\)-intercepts of \(y=x^2-x-6\)?
Compute the discriminant of \(x^2-x-6\).
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