Answer:
a. -2
b. 48, -96, 192
Step-by-step explanation:
.5, .76 are terminating
the square root of two, pi are terminating
5/8 because it is 0.625, while 2/3 is 0.66666...
<u>Prove that:</u>

<u>Proof: </u>
We know that, by Law of Cosines,
<u>Taking</u><u> </u><u>LHS</u>
<em>Substituting</em> the value of <em>cos A, cos B and cos C,</em>



<em>On combining the fractions,</em>

<em>Regrouping the terms,</em>



LHS = RHS proved.