$$2\left(4x^2+y^2\right)\left(4x^2-y^2\right)$$

prime

$$2\left(4x^2+y^2\right)\left(2x+y\right)\left(2x-y\right)$$

$$\left(4x^2+y^2\right)\left(2x+y\right)\left(2x-y\right)$$

y = $$\left\{\pm\frac{5}{2}\right\}$$

y = {-2, 3}

y = {-4, 4}

y = {-3, 5}

Prime

( x - 9 ) ( x + 9 )

( x + 9 ) ( x + 9 )

( x - 9 ) ( x - 9 )

(r + 3t) (r - 3t)

(r - 3t) (r - 3t)

(3r + t) (3r - t)

(r + 3t) (r + 3t)

Because 4 is not a perfect cubed number.

Because 4 is not a perfect squared number.

Because 49 is not a perfect squared number.

Because we can't factor using difference of two squares if it is addition sign.

(2m + 7) (2m - 7)

(2m - 7) (2m - 7)

(m² + 7) (m² - 7)

Can't factor using Diff. of Squares