Convert (x+1)(x-1) to Its Standard Quadratic Form

Question

Find the standard representation of the following function

f(x)=(x+1)(x1) f(x)=(x+1)(x-1)

Video Solution

Step-by-Step Solution

To solve this problem and find the standard representation of the function f(x)=(x+1)(x1) f(x) = (x+1)(x-1) , we will expand the product using the distributive property, often recalled as FOIL (First, Outer, Inner, Last) for the product of two binomials.

Let's proceed step-by-step:

  • Step 1: Apply the distributive property:
    f(x)=(x+1)(x1) f(x) = (x+1)(x-1) would become:
  • First terms: xx=x2 x \cdot x = x^2
  • Outer terms: x(1)=x x \cdot (-1) = -x
  • Inner terms: 1x=x 1 \cdot x = x
  • Last terms: 1(1)=1 1 \cdot (-1) = -1

Step 2: Combine all the terms obtained from the FOIL method:
x2x+x1 x^2 - x + x - 1

Step 3: Simplify the expression by combining like terms:
The terms x-x and xx cancel each other out, simplifying to:
f(x)=x21 f(x) = x^2 - 1

Thus, the standard representation of the function is f(x)=x21 f(x) = x^2 - 1 .

Answer

f(x)=x21 f(x)=x^2-1