Q. \(x^{2}+2x-63=0\)
Answer
We solve the quadratic \(x^2+2x-63=0\) by factoring.
Find two numbers that multiply to \(-63\) and add to \(2\): \(9\) and \(-7\).
\[
x^2+2x-63=(x+9)(x-7)=0
\]
So \(x+9=0\) or \(x-7=0\).
\[
x=-9 \quad \text{or} \quad x=7
\]
Final result: \(x=7\) or \(x=-9\).
Detailed Explanation
We want to solve the quadratic equation:
\[
x^2 + 2x – 63 = 0
\]
Step 1: Factor the quadratic.
A quadratic of the form \(ax^2 + bx + c\) can be factored if we find two numbers whose product is \(ac\) and whose sum is \(b\).
Here, \(a = 1\), \(b = 2\), and \(c = -63\).
So we need two numbers \(m\) and \(n\) such that:
\[
m \cdot n = -63
\]
\[
m + n = 2
\]
Step 2: Find the numbers.
Because the product is \(-63\), one number must be positive and the other negative.
Check factor pairs of \(63\): \(1\) and \(63\), \(3\) and \(21\).
We test which pair gives a sum of \(2\):
\[
(-1) + 3 = 2
\]
So we take \(m = 3\) and \(n = -1\). Their product is:
\[
3 \cdot (-1) = -3
\]
That is not \(-63\), so we must use the factor pair method more carefully: we need factors that multiply to \(-63\) and add to \(2\).
Try these factor pairs of \(-63\):
\(63\) and \(-1\):
\[
63 + (-1) = 62 \quad \text{not } 2
\]
\(21\) and \(-3\):
\[
21 + (-3) = 18 \quad \text{not } 2
\]
\(9\) and \(-7\):
\[
9 + (-7) = 2
\]
Great! So the two numbers are \(9\) and \(-7\).
Step 3: Rewrite and factor the quadratic.
Now factor the expression:
\[
x^2 + 2x – 63 = (x+9)(x-7)
\]
Step 4: Set each factor equal to zero.
Using the zero product property:
\[
(x+9)(x-7)=0
\]
\[
x+9=0 \quad \text{or} \quad x-7=0
\]
Step 5: Solve each equation.
First equation:
\[
x+9=0
\]
\[
x=-9
\]
Second equation:
\[
x-7=0
\]
\[
x=7
\]
Final Answer:
The solutions to \(x^2 + 2x – 63 = 0\) are:
\[
x = -9 \quad \text{and} \quad x = 7
\]
Graph
Algebra FAQ
How do you solve \(x^2+2x-63=0\) by factoring?
What is the quadratic formula for \(x^2+2x-63=0\), and what are the solutions?
What are the discriminant \(\Delta\) and what do they imply?
How do you complete the square to solve \(x^2+2x-63=0\)?
How can you check the solutions quickly?
Does the graph of \(y=x^2+2x-63\) intersect the \(x\)-axis at these points?
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