What is the first step in solving the equation x2 - 25 = 0?
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Answer:
Step-by-step explanation:
So we have the expression:
And we wish to factor it.
First, let's make a substitution. Let's let u be equal to x². Therefore, our expression is now:
This is a technique called quadratic u-substitution. Now, we can factor in this form.
We can use the numbers -3 and -2. So:
For the first two terms, factor out a u.
For the last two terms, factor out a -3. So:
Grouping:
Now, substitute back the x² for u:
And this is the simplest form.
And we're done!