b) \(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x+1\right)-\left(x-6\right)\)
\(\Leftrightarrow\left(3x+2\right)2x+\left(3x+2\right)9-x.\left(6x+1\right)-2.\left(6x+1\right)=x+1-x+6\)
\(\Leftrightarrow6x^2+4x+27x+18-6x^2-x-12x-2=7\)
\(\Leftrightarrow18x+16=7\)
\(\Leftrightarrow18x=-9\)
\(\Leftrightarrow x=\frac{-1}{2}\)
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