[tex] \frac{-12}{P} [/tex] ([tex] \frac{3P}{2} + \frac{P}{2} [/tex] )

[tex]- \frac{12}{p} ( \frac{3P}{2}+ \frac{P}{2} )[/tex]
= [tex]- \frac{12}{P} ( \frac{4P}{2} )[/tex]
= [tex]- \frac{48P}{2P} [/tex]
= -24

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