Q. \(x^2 + 5x – 24\)
Answer
Factor the quadratic by finding two numbers that multiply to \(-24\) and add to \(5\). Those numbers are \(8\) and \(-3\).
\[
x^2+5x-24=(x+8)(x-3)
\]
Set each factor equal to zero:
\[
x+8=0 \Rightarrow x=-8,\quad x-3=0 \Rightarrow x=3
\]
Final result: \((x+8)(x-3)=0\), so \(x=-8\) or \(x=3\).
Detailed Explanation
We want to simplify the expression \(x^2 + 5x – 24\). A common first goal is to factor it, since factoring helps find useful structure (like roots).
Step 1: Set up factoring
We look for two numbers \(m\) and \(n\) such that
\[
x^2 + 5x – 24 = (x + m)(x + n).
\]
When you expand \((x+m)(x+n)\), you get
\[
(x+m)(x+n) = x^2 + (m+n)x + mn.
\]
So we need:
- \(m+n = 5\)
- \(mn = -24\)
Step 2: Find the numbers
We need two numbers whose product is \(-24\) and whose sum is \(5\).
List factor pairs of \(-24\):
- \(1\) and \(-24\) (sum \(=-23\))
- \(2\) and \(-12\) (sum \(=-10\))
- \(3\) and \(-8\) (sum \(=-5\))
- \(4\) and \(-6\) (sum \(=-2\))
- \(-1\) and \(24\) (sum \(=23\))
- \(-2\) and \(12\) (sum \(=10\))
- \(-3\) and \(8\) (sum \(=5\))
The pair \(-3\) and \(8\) works because
- \((-3) + 8 = 5\)
- \((-3)\cdot 8 = -24\)
Step 3: Write the factored form
Substitute \(m=-3\) and \(n=8\) into \((x+m)(x+n)\):
\[
x^2 + 5x – 24 = (x – 3)(x + 8).
\]
Final Answer
\[
x^2 + 5x – 24 = (x – 3)(x + 8).
\]
Graph
Algebra FAQ
How do you factor \(x^2+5x-24\)?
What are the roots of \(x^2+5x-24=0\)?
Can you use the quadratic formula to solve \(x^2+5x-24=0\)?
What is the discriminant of \(x^2+5x-24\)?
What is \(x^2+5x-24\) in completed square form?
What is the vertex of \(y=x^2+5x-24\)?
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