Definition 1: Perfect squares are numbers or expressions that are the product of a
number or expression multiplied to itself (7 times 7 is 49, so 49 is a
perfect square).
Definition 2: <span>Binomials are algrebraic expressions containing only two terms.</span><span />
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Definition 3: Trinomials are algebraic expressions that contain three terms. </span><span />
Perfect square trinomials are algebraic expressions with three terms that are created by multiplying a binomial to itself. There are two formulas for perfect square trinomials:

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From these formulas you can see that:
A. <span>"Neither of the perfect squares can have a minus sign" is true statement;
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B. "<span>The first and third terms must be perfect squares" is true statement;
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C. "<span>If the perfect square terms are

and

then the other term must be

" is false statement;
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D. "<span>None of the above is a property of a perfect square trinomial" is consequently false statement.
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What question do you need help on?
2500 in standard form is 2.5 × 10³
Option B. 13π/6 and Option D. 5π/6
To get the reference angle π/6 for the given angles we will check each angle given in the options.
A. 8π/6
Since 8π/6 means 240° which lies in 3rd quadrant. Therefore reference angle of 240°= 240-180 = 60° or π/3
B. 13π/6
13π/6 means 390° which lies in first quadrant.
Therefore reference angle = 390-360 = 30° or π/6
C. 3π/6
Since 3π/6 means 90° therefore reference angle of 90° is the same as 90°.
Or the reference angle is = π/2
D. 5π/6
5π/6 means angle is 150° which lies in second quadrant therefore reference angle of 150° = 180-150 = 30° or π/6
answer is Option B and D.