Verify the Equation: x⁴-16 = (x²-4)(4+x²) - Polynomial Identity Check

Question

Is the value of the following equation true or false?

x416=(x24)(4+x2) x^4-16=(x^2-4)(4+x^2)

Video Solution

Solution Steps

00:00 Is the equation correct?
00:15 We'll use the commutative law
00:27 We'll use the abbreviated multiplication formulas
00:47 Let's calculate 4 squared
00:52 The equation is correct
00:56 And this is the solution to the question

Step-by-Step Solution

To solve this problem, let's follow these steps:

  • Step 1: Factor the left-hand side x416 x^4 - 16 using the difference of squares.
  • Step 2: Expand the right-hand side expression.
  • Step 3: Verify if both sides are equivalent after simplification.

Now, let's evaluate each step:

Step 1:
The expression on the left-hand side is x416 x^4 - 16 .
This can be viewed as (x2)242 (x^2)^2 - 4^2 ,
which is a difference of squares. Therefore, we can factor it as:
(x24)(x2+4)(x^2 - 4)(x^2 + 4).

Step 2:
Next, consider the right-hand side, (x24)(4+x2) (x^2 - 4)(4 + x^2) .
To expand, use distribution (FOIL method):
- First: x2×4=4x2 x^2 \times 4 = 4x^2
- Outer: x2×x2=x4 x^2 \times x^2 = x^4
- Inner: 4×4=16 -4 \times 4 = -16
- Last: 4×x2=4x2 -4 \times x^2 = -4x^2
Combine these terms:
x4+4x2164x2=x416 x^4 + 4x^2 - 16 - 4x^2 = x^4 - 16 .

Step 3:
The expanded term, x416 x^4 - 16 , matches the factored left-hand side expression, (x24)(x2+4) (x^2-4)(x^2+4) , showing that both sides are equivalent.

Therefore, the equation x416=(x24)(4+x2) x^4 - 16 = (x^2 - 4)(4 + x^2) is True for all values of x x .

Answer

True