The SAT Math exam will throw some questions at you where you’ll be expected to know how to perform a FOIL operation—where you multiply a polynomial in the order, First, Outer, Inner, and Last.

The following practice questions ask you to find the product of two binomials and the value of a variable using the FOIL method.

Practice questions

  1. Which of the following is the product of these two binomials? x + 2 x – 5 A. x2 10 B. x2 + 10 C. x2 3x – 10 D. x2 + 3x – 10
  2. If x – 2 is a factor of x2 + 6xy2 and y > 0, what is the value of y? Note: this would be a grid-in question. Because there are no multiple-choice answers, you need to supply the correct answer.

Answers and explanations

  1. The correct answer is Choice (C). Product means "multiply." This is a simple FOIL operation: (x + 2)(x – 5) = x2 – 3x –10
  2. The correct answer is 4. If x – 2 is a factor of the polynomial, then for the middle part of the polynomial to be 6x, the other factor must be (x + 8). Write out these factors and FOIL the expression: (x – 2)(x + 8) = (x2 + 6x – 16) The given polynomial is x2 + 6xy2, so this means that y2 = 16, and because y is positive, it must equal 4.

About This Article

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Ron Woldoff is the founder of National Test Prep, where he helps students prepare for the SAT, GMAT, and GRE. He is the author of several books, including GRE For Dummies and 1,001 GRE Practice Questions For Dummies.

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