The special products can be used to perform selected multiplications. On the left, we use (x+y)(x-y) = x2-y2. On the right, (x-y)2 = x2-2xy+y2. Use special products to evaluate each expression. < SEE SAMPLE B> 712
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Recognize that the expression 71^2 is a perfect square, which can be evaluated using the special product formula for the square of a binomial: \((x + y)^2 = x^2 + 2xy + y^2\).
Rewrite 71 as a sum of two numbers that are easier to square, for example, \$71 = 70 + 1$.
Apply the formula \((x + y)^2 = x^2 + 2xy + y^2\) with \(x = 70\) and \(y = 1\).
Calculate each term separately: \(x^2 = 70^2\), \$2xy = 2 imes 70 imes 1\(, and \)y^2 = 1^2$.
Add the three results together to find the value of \$71^2$.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Special Products Formulas
Special products are algebraic identities that simplify multiplication, such as the difference of squares (x + y)(x - y) = x² - y² and the square of a binomial (x - y)² = x² - 2xy + y². Recognizing these patterns helps quickly expand or evaluate expressions without full multiplication.
The difference of squares formula states that the product of a sum and difference of the same two terms equals the difference of their squares: (a + b)(a - b) = a² - b². This is useful for simplifying expressions and evaluating products efficiently.
Solving Quadratic Equations by Completing the Square
Square of a Binomial
Squaring a binomial involves expanding (a ± b)² into a² ± 2ab + b². For example, (x - y)² = x² - 2xy + y². This formula allows quick calculation of squares of numbers expressed as sums or differences, such as 71² by rewriting 71 as (70 + 1).