Jika T(3x² + 2 - 3x) = 5x + 7, maka nilai T^-1(12)=

[tex]
\text{Misalkan }y=t(3x^2-3x+2)\Leftrightarrow t^{-1}(y)=3x^2-3x+2\\
\text{selanjutnya, }\\
t(3x^2-3x+2)=5x+7\\
\Leftrightarrow y=5x+7\\
\Leftrightarrow 5x=y-7\\
\Leftrightarrow x=\frac{y-7}{5}\\
\Leftrightarrow 3x^2-3x+2=3\left(\frac{y-7}{5}\right)^2-3\left(\frac{y-7}{5}\right)+2\\
\Leftrightarrow t^{-1}(y)=3\left(\frac{y-7}{5}\right)^2-3\left(\frac{y-7}{5}\right)+2\\
\Leftrightarrow t^{-1}(12)=3\left(\frac{12-7}{5}\right)^2-3\left(\frac{12-7}{5}\right)+2\\
\Leftrightarrow t^{-1}(12)=3(1)^2-3(1)+2\\
\Leftrightarrow t^{-1}(12)=2
[/tex]