Question

(2a-1)^3-8a^3+5 при a=-2

Answer 1

(2a-1)³-8a³+5=8а³-12а²+6а-1-8а³+5=-12а²+6а+4
при  а=-2
-12·(-2)²+6·(-2)+4=-48-12+4=-56

Answer 2

I can help you with your math problem. Here is the detailed solution:

$$ \begin{aligned} (2a-1)^3-8a^3+5 \text{ при } a=-2 &= (2(-2)-1)^3-8(-2)^3+5 \\ &= (-5)^3-8(-8)+5 \\ &= -125+64+5 \\ &= -56 \end{aligned} $$

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