Expanding (x + 1)(x + 3) into Standard Form
The expression (x + 1)(x + 3) is in factored form. To write it in standard form, we need to expand it. Here's how:
Using the FOIL Method
The FOIL method is a mnemonic for remembering how to multiply two binomials:
- First: Multiply the first terms of each binomial.
- Outer: Multiply the outer terms of the binomials.
- Inner: Multiply the inner terms of the binomials.
- Last: Multiply the last terms of each binomial.
Let's apply this to our expression:
- F: x * x = x²
- O: x * 3 = 3x
- I: 1 * x = x
- L: 1 * 3 = 3
Now, we add all the terms together: x² + 3x + x + 3
Combining like terms, we get:
x² + 4x + 3
This is the standard form of the expression (x + 1)(x + 3).
Using the Distributive Property
We can also use the distributive property to expand the expression:
(x + 1)(x + 3) = x(x + 3) + 1(x + 3)
Distributing further:
= x² + 3x + x + 3
Combining like terms, we get:
x² + 4x + 3
This confirms that both methods lead to the same answer.
Conclusion
The standard form of the expression (x + 1)(x + 3) is x² + 4x + 3. This form is useful for various algebraic operations, like solving equations, finding the roots of the expression, or graphing the function represented by the expression.