Question

Remove the brackets from the given expression: $(x+1)(x-3)$

Short answer

Question: Remove the brackets from the expression $(x+1)(x-3)$. Answer: $x^2-2x-3$

Step-by-step solution

Apply the FOIL method (First, Outer, Inner, Last)

Multiply the first terms of each parentheses, the outer terms, the inner terms, and the last terms. First: $x\cdot x=x^2$ Outer: $x\cdot (-3)=-3x$ Inner: $1\cdot x=x$ Last: $1\cdot (-3)=-3$

Combine the terms

Now, we will add all the resulting terms together: $x^2-3x+x-3$

Simplify the expression

Combine any like terms in the expression: $x^2-2x-3$ The simplified expression without brackets is $x^2-2x-3$.

Key concepts

FOIL Method

The FOIL method is an essential technique in algebra. It helps when multiplying two binomials, which are algebraic expressions with two terms. The name "FOIL" stands for First, Outer, Inner, Last, representing the sequence of multiplying the terms of each binomial.
When you have an expression like $(x+1)(x-3)$, you apply FOIL as follows:

• First: Multiply the first terms from each binomial: $x\cdot x=x^2$.
• Outer: Multiply the outer terms: $x\cdot (-3)=-3x$.
• Inner: Multiply the inner terms: $1\cdot x=x$.
• Last: Multiply the last terms: $1\cdot (-3)=-3$.

By multiplying as per the FOIL order, you ensure that every term is accurately accounted for. This results in the expression: $x^2-3x+x-3$. If you follow these steps, you'll correctly multiply any two binomials using this method.

Algebraic Expressions

Algebraic expressions are combinations of variables, numbers, and operators (like addition and multiplication). They can represent real-world situations and allow solving complex problems. Each part of the expression can have a specific role, such as coefficients (the numbers multiplying the variables) or constants (the standalone numbers).
For example, in the expression $(x+1)(x-3)$, each binomial is an algebraic expression in itself. The variable $x$ represents a number, and the constants 1 and -3 modify the variable's effect in calculations.
Algebraic expressions involve operations:

• Addition: Combining values, like $x+1$.
• Multiplication: Distributing terms across each other, as seen with $(x+1)(x-3)$.

Working with algebraic expressions requires understanding these components and practicing how they interact, especially during operations like the FOIL method.

Simplifying Expressions

Simplifying expressions is about rewriting them in their most efficient form. This makes them easier to understand or solve. After applying the FOIL method to a pair of binomials, the next step is to simplify the resulting expression.
For instance, after applying FOIL to $(x+1)(x-3)$, you get $x^2-3x+x-3$. Here's the process to simplify it:

• Look for Like Terms: These are terms that have the same variable raised to the same power. In this case, $-3x$ and $+x$ are like terms.
• Combine Like Terms: Add them together: $-3x+x=-2x$.

After simplifying, the expression becomes $x^2-2x-3$. Simplifying is crucial, as it leads to a cleaner, more workable expression that can be further analyzed or solved.