Question

What is the following product ?

Answer 1

Choice b is correct. 7x²-12x√14+72 is answer.

Explanation:

We have given the expression.

We have to find the product of given expression.

For this, we use the following formula:

(a-b) = a²-2ab+b²

Rewrite the given expression in the form:

(x√7 - 3√8)(x√7 - 3√8) = (x√7 - 3√8)²

Using the above formula in this expression.

(x√7 - 3√8)² = (x√7)²- 2(x√7)(3√8) + (3√8)²

(x√7 - 3√8)² = 7x² - 6x√56 + 72

(x√7 - 3√8)² = 7x²-6x *2√14 +72

(x√7 - 3√8)² = 7x²-12x√14 +72

This is the product of given expression.

Answer 2

The correct answer is option B). 7x² -12x√14 + 72

Explanation:

Identity

(a - b)² = a² - 2ab + b²

Find the product

It is given that ( x√7 - 3√8)(x√7 - 3√8)

(x√7 - 3√8)(x√7 - 3√8) = (x√7 - 3√8)²

(x√7 - 3√8)² = (x√7)² - 2*x√7*3√8 +(3√8)²

= 7x² - 6x√56 + 72

= 7x² - 6x*2√14 + 72

= 7x² - 12x√14 + 72

Therefore the correct answer is option B). 7x² - 12x√14 + 72