This is called a difference of squares which always factors according to the rule for factoring the difference of squares....
(a^2+b^2)=(a+b)(a-b) in this case:
9w^2-16 so
(3w-4)(3w+4)
We break all the bracket out :
-0.75 + 2/5 + 0.4 - 3/4
2/5 = 0.4
-3/4 = -0.75
So, we have : -0.75 + 0.4 + 0.4 - 0.75
= (-0.75 - 0.75) + (0.4 + 0.4) = -1.5 + 0.8 = -0.7
