\(A=\left(t+2\right)\left(3t-1\right)-t\left(3t+3\right)-2t+7\)
\(=3t^2-t+6t-2-3t^2-3t-2t+7\)
\(=\left(3t^2-3t^2\right)-\left(t-6t+3t+2t\right)-\left(2-7\right)\)
\(=0-0-\left(-5\right)=5\)
A=(t+2)(3t−1)−t(3t+3)−2t+7A=(t+2)(3t−1)−t(3t+3)−2t+7
=3t2−t+6t−2−3t2−3t−2t+7=3t2−t+6t−2−3t2−3t−2t+7
=(3t2−3t2)−(t−6t+3t+2t)−(2−7)=(3t2−3t2)−(t−6t+3t+2t)−(2−7)
=0−0−(−5)=5