(3.5p-1.2k)(3.5p+1.2k)

To simplify the expression (3.5p-1.2k)(3.5p+1.2k), you can use the distributive property.

The distributive property states that for any variables a, b, and c, the product of a and (b + c) is equal to the product of a and b plus the product of a and c.

So, in this case, we have:

(3.5p - 1.2k)(3.5p + 1.2k)

= (3.5p)(3.5p) + (3.5p)(1.2k) - (1.2k)(3.5p) - (1.2k)(1.2k)

= 12.25p^2 + 4.2pk - 4.2pk - 1.44k^2

= 12.25p^2 - 1.44k^2

So, the simplified expression is 12.25p^2 - 1.44k^2.