\(P=\dfrac{1}{x+2}+\dfrac{1}{\left(x+2\right)\left(4x+7\right)}\)
\(=\dfrac{4x+7}{\left(x+2\right)\left(4x+7\right)}+\dfrac{1}{\left(x+2\right)\left(4x+7\right)}\)
\(=\dfrac{4x+8}{\left(x+2\right)\left(4x+7\right)}=\dfrac{4\left(x+2\right)}{\left(x+2\right)\left(4x+7\right)}\)
\(=\dfrac{4}{4x+7}\)
2.
\(x^2-4=0\Leftrightarrow\left(x-2\right)\left(x+2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=2\\x=-2\left(ktm\right)\end{matrix}\right.\)
\(\Rightarrow P=\dfrac{4}{4.2+7}=\dfrac{4}{15}\)
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