When b greater than or equal to zero, 12a^2b^3 – a^6 – b^9 a) always is less than or equal to 64 b) always negative c) always greater than 64 d) always lies in the internal [60,64]
what about a?
The answer must be A. I will disprove all others, leaving only A. B .. a = 0, b = 0, so the equation =0, which is NOT negative, so B is wrong. C .. Same case as B. 0 is less than 64, so C is wrong. D .. Same case as B and C haha. 0 is not in that interval.
The value of "a" is unknown. It was not given in the question.
ah so good @mathandphysics
thanks for medal :)
U r welcome.
Also, you knew it couldn't be B because all negative numbers are also encompassed in part A, so if B was right, A would automatically be right also. Just a side-note.
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