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If n < 0 And 4x²+mx+9=(2x+n)², What Is The Value Of m+n? A. -15 B. -9 C. -3 D. 12

User Stasl
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Answer: A (-15)

Explanation:

Expanding the right side,

4x^2 + mx + 9 = 4x^2 + 4nx +n^2

Comparing both sides, we see that

9 = n^2

m = 4n

Therefore, n = -3 and m = 4(-3) = -12

m + n = -3 + (-12) = -15

User Pedro Brost
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