Welcome to bracket expansion! Today we'll learn how to multiply algebraic expressions using the FOIL method.Let's start with a simple example: x plus 2, multiplied by x plus 3.FOIL is a method that helps us multiply two brackets systematically. It stands for First, Outer, Inner, and Last terms.Let's separate our brackets to see how each term multiplies with the others.First, we multiply the first terms in each bracket: x times x gives us x squared.Next, we multiply the outer terms: x from the first bracket times 3 from the second bracket gives us 3x.For the inner terms, we multiply 2 from the first bracket by x from the second bracket, giving us 2x.Finally, we multiply the last terms: 2 times 3 equals 6.Now let's write out all our terms.Notice that we have two terms with x: 3x and 2x. These are like terms and can be combined.When we combine the like terms and write everything in standard form, our final answer is x squared plus 5x plus 6.Now we'll tackle expanding three brackets: x plus one, times x plus two, times x plus three.We'll break this down into two manageable steps.First, let's expand just the first two brackets using the FOIL method we learned earlier.Combining like terms from our FOIL expansion.Now for step two, we'll multiply our result by the third bracket.We multiply each term in our first result by both terms in the third bracket.This gives us several terms that we need to combine carefully.After combining like terms, we get our final result.Notice how our terms follow a pattern of decreasing powers of x.The powers of x decrease systematically from x cubed down to the constant term.One of the most common mistakes in bracket expansion is forgetting to change signs when multiplying by negative terms.We can verify our answers by substituting simple values for x. Let's try x equals 1.Another common mistake is missing terms, especially in triple bracket expansions. Always check that no powers are skipped.Here are three strategic values we can use to check our expansions.Let's see how these values help us verify a quadratic expansion.
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