Special Products of Polynomials

Key Questions

  • The general form for multiplying two binomials is:
    (x+a)(x+b)=x^2+(a+b)x+ab

    Special products:

    1. the two numbers are equal, so it's a square:
      (x+a)(x+a)=(x+a)^2=x^2+2ax+a^2, or
      (x-a)(x-a)=(x-a)^2=x^2-2ax+a^2
      Example : (x+1)^2=x^2+2x+1
      Or: 51^2=(50+1)^2=50^2+2*50+1=2601

    2. the two numbers are equal, and opposite sign:
      (x+a)(x-a)=x^2-a^2
      Example : (x+1)(x-1)=x^2-1
      Or: 51*49=(50+1)(50-1)=50^2-1=2499

  • Answer:

    A trinomial that when factored gives you the square of a binomial

    Explanation:

    Given: What is a perfect square binomial?

    A perfect square binomial is a trinomial that when factored gives you the square of a binomial.

    Ex. (a+b)^2 = a^2 + 2ab + b^2

    Ex. (2a + 3b)^2 = 4a^2 + 12ab + 9b^2

Questions