The answer is x^2-2^2
X^2-4

Formula works when n=1
Assume the formula also works, when n=k.
Prove that the formula works, when n=k+1

Since the formula has been proven with n=1 and n=k+1, it is true. 
The correct answer is: [D]: " 4xy + 16x − 4y² − 16y " .
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Explanation:
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Given:
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" (2x <span>− 2y) (2y + 8) " ; Simplify .
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We starting by "expanding" the expression.
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<u>Note</u>: " (a + b)(c + d) = ac + ad + bc + bd " ;
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</span>→ (2x * 2y) + (2x * 8) + (-2y * 2y) + (-2y * 8) ;
= 4xy + 16x + (- 4y² ) + (-16y) ;
= 4xy + 16x − 4y² <span>− 16y ;
</span>→ which is: "Answer choice: [D]: " 4xy + 16x − 4y² − 16y " .
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Answer:
For a quadratic function in standard form, y=ax2+bx+c
the axis of symmetry is a vertical line x=−b2a .
Step-by-step explanation:
Hope this helps !