Q. \(x^2 – 3x – 10 = 0\)
Answer
We solve the quadratic \(x^2-3x-10=0\) by factoring. Find two numbers that multiply to \(-10\) and add to \(-3\): \(2\) and \(-5\).
So, \((x-5)(x+2)=0\).
Thus \(x-5=0\) gives \(x=5\), and \(x+2=0\) gives \(x=-2\).
Final Result: \(\,x=5\) or \(\,x=-2\).
Detailed Explanation
We want to solve the equation
\[x^2 – 3x – 10 = 0.\]
Step 1: Identify the quadratic form
A quadratic equation has the form
\[ax^2 + bx + c = 0.\]
Here, we can match coefficients:
\[a = 1,\quad b = -3,\quad c = -10.\]
Step 2: Factor the quadratic
The goal is to rewrite \(x^2 – 3x – 10\) as a product of two binomials:
\[(x + m)(x + n) = x^2 + (m+n)x + mn.\]
We need \(m+n = -3\) and \(mn = -10\).
Now list factor pairs of \(-10\):
- \(1 \cdot -10 = -10\)
- \(-1 \cdot 10 = -10\)
- \(2 \cdot -5 = -10\)
- \(-2 \cdot 5 = -10\)
Check which pair adds to \(-3\):
- \(2 + (-5) = -3\) ✓
So \(m = 2\) and \(n = -5\). Therefore,
\[x^2 – 3x – 10 = (x + 2)(x – 5).\]
Step 3: Use the zero product property
If a product is zero, then at least one factor must be zero. So:
\[(x + 2)(x – 5) = 0.\]
This gives two equations:
\[x + 2 = 0 \quad \text{or} \quad x – 5 = 0.\]
Step 4: Solve each linear equation
First:
\[x + 2 = 0.\]
Subtract \(2\) from both sides:
\[x = -2.\]
Second:
\[x – 5 = 0.\]
Add \(5\) to both sides:
\[x = 5.\]
Final Answer
The solutions to the equation \(x^2 – 3x – 10 = 0\) are:
\[x = -2 \quad \text{or} \quad x = 5.\]
Graph
Algebra FAQ
Solve \(x^2-3x-10=0\) using the quadratic formula.
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Solve the equation step by step.
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