tailieunhanh - SAT math essentials part 5

Tham khảo tài liệu 'sat math essentials part 5', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | --------------------------------------- ALGEBRA REVIEW ----------------------------------------------- FOIL The FOIL method is used when multiplying binomials. FOIL represents the order used to multiply the terms First Outer Inner and Last. To multiply binomials you multiply according to the FOIL order and then add the products. Example 4x 2 9x 8 F 4x and 9x are the first pair of terms. O 4x and 8 are the outer pair of terms. I 2 and 9x are the inner pair of terms. L 2 and 8 are the last pair of terms. Multiply according to FOIL 4x 9x 4x 8 2 9x 2 8 36x2 32x 18x 16 Now combine like terms 36x2 50x 16 Practice Question Which of the following is the product of 7x 3 and 5x 2 a. 12x2 6x 1 b. 35x2 29x 6 c. 35x2 x 6 d. 35x2 x 6 e. 35x2 11x 6 Answer c. To find the product follow the FOIL method 7x 3 5x - 2 F 7x and 5x are the first pair of terms. O 7x and 2 are the outer pair of terms. I 3 and 5x are the inner pair of terms. L 3 and 2 are the last pair of terms. Now multiply according to FOIL 7x 5x 7x 2 3 5x 3 2 35x2 - 14x 15x - 6 Now combine like terms 35x2 x 6 75 -------------------------------------- ALGEBRA REVIEW ---------------------------------------------- Factoring Factoring is the reverse of multiplication. When multiplying you find the product of factors. When factoring you find the factors of a product. Multiplication 3 x y 3x 3y Factoring 3x 3y 3 x y Three Basic Types of Factoring Factoring out a common monomial 18x2 9x 9x 2x 1 ab cb b a c Factoring a quadratic trinomial using FOIL in reverse x2 x 20 x 4 x 4 x2 6x 9 x 3 x 3 x 3 2 Factoring the difference between two perfect squares using the rule a2 b2 a b a b x2 81 x 9 x 9 x2 49 x 7 x 7 Practice Question Which of the following expressions can be factored using the rule a2 b2 a b a b where b is an integer a. x2 27 b. x2 40 c. x2 48 d. x2 64 e. x2 72 Answer d. The rule a2 b2 a b a b applies to only the difference between perfect squares. 27 40 48 and 72 are not perfect squares. 64 is a perfect square so x2 64 .