Simplify (3-4√2)^2

Question

Simplify the expression (3-4√2)^2

 

I worked this out as

3^2-4^2(2)

9-16(2)

9-32

-23

 

Am I solving this correctly?

Answer 1

You can use the binomial expansion:

 

(a - b)² = a² - 2ab + b²

 

(3 - 4√2)² = 3² - 2[3(4√2)] + (4√2)² = 9 - 24√2 + 16(2) = 9 - 24√2 + 32 = 41 - 24√2

Answer 2

(3 - 4√2)²

(3 - 4√2)(3 - 4√2)           USE FOIL

(3)(3) + (3)(-4√2) + (3)(-4√2) + (-4√2)(-4√2)

9 - 12√2 - 12√2 + (14)(2)

 

Can you continue?