Question

Answer 1

\(a,x=1\Leftrightarrow A=\dfrac{9+6+5}{3+2}=\dfrac{20}{5}=4\\ b,B=\dfrac{3x+2-3x+2+3x-6}{\left(3x-2\right)\left(3x+2\right)}=\dfrac{3x-2}{\left(3x-2\right)\left(3x+2\right)}=\dfrac{1}{3x+2}\\ c,B=-\dfrac{1}{7}\Leftrightarrow3x+2=-7\\ \Leftrightarrow x=-3\left(tm\right)\\ d,P=\dfrac{A}{B}=\dfrac{9x^2+6x+5}{3x+2}\cdot\left(3x+2\right)=9x^2+6x+1+4=\left(3x+1\right)^2+4\ge4\\ P_{min}=4\Leftrightarrow x=-\dfrac{1}{3}\left(tm\right)\)

Answer 2

a: \(A=\dfrac{9+6+5}{3+2}=4\)