Question

What is the following product?
(xsqrt7-3sqrt8)(xsqrt7-3sqrt8)

Answer 1

7x^2 -12x(sqrt 14) + 72

Explanation:

Use foil and you get

x^2(7) - (3x(sqrt56))+(-3x(sqrt56))+ 9(8)

= The inner terms simplify to -6x(sqrt14) + (-6x(sqrt14)) = -12x(sqrt14)

so answer is

7x^2 -12x(sqrt 14) + 72