Question 31 of 43intermediate🔍 AnalyzeShort Answer2 marks

Can you see how x - y is a factor of x4x^{4} - y4y^{4}?

Correct Answer

Yes, we can clearly see that x - y is a factor of x4x^{4} - y4y^{4} by using algebraic identities.

First, we can express x4x^{4} - y4y^{4} as the difference of two squares: (x2x^{2})^2 - (y2y^{2})^2. Using the identity for the difference of squares, this becomes (x2x^{2} - y2y^{2})(x2x^{2} + y2y^{2}).

We already know from the identity x2x^{2} - y2y^{2} = (x - y)(x + y) that x2x^{2} - y2y^{2} contains (x - y) as a factor. By substituting this into our previous expression, we get x4x^{4} - y4y^{4} = (x - y)(x + y)(x2x^{2} + y2y^{2}). This directly shows that x - y is a factor of x4x^{4} - y4y^{4}.

Exercise: Think and Reflect | Q: 2 | (Chapter: 18)
For More Understanding

Explanation

The textbook context demonstrates that x4x^{4} - y4y^{4} can be factored as (x2x^{2} - y2y^{2})(x2x^{2} + y2y^{2}). Since x2x^{2} - y2y^{2} further factors into (x - y)(x + y), substituting this back clearly shows (x - y) as a common factor of the expression.

Solution Steps

  1. Step 1: Express x4x^{4} - y4y^{4} as (x2x^{2})^2 - (y2y^{2})^2 = (x2x^{2} - y2y^{2})(x2x^{2} + y2y^{2})

  2. Step 2: Substitute the identity x2x^{2} - y2y^{2} = (x - y)(x + y) into the expression

  3. Step 3: Conclude x4x^{4} - y4y^{4} = (x - y)(x + y)(x2x^{2} + y2y^{2}), proving x - y is a factor.