Answer
a. Statement: $\forall$ actions x, $\exists$ a reaction y, such that x and y are equal and opposite.
b. Negation: $\exists$ an action x, such that $\forall$ reactions y, x isn't equal y or x isn't opposite to y. There is an action that is not equal or is not opposite to any reaction.
Work Step by Step
Recall the negation of a for all statement:
~($\forall x$ in D, P(x)) $\equiv \exists x$ in D such that ~P(x).
Recall the negation of an exists statement:
~($\exists x$ in D, P(x)) $\equiv \forall x$ in D such that ~P(x).
To negate a multiply quantified statement, apply the laws in stages moving left to right along the sentence.
