Substitute t=5 into E, F, and G, then determine which expressions yield the same result and why, and finally expand E, F, and G.

$$E = 3t(-2) = 3(5)(-2) = 15(-2) = -30$$

The value of E is $\boxed{-30}$.

$$F = 3t(2-t) = 3(5)(2-5) = 15(-3) = -45$$

The value of F is $\boxed{-45}$.

$$G = (-2)3t = (-2)3(5) = (-6)(5) = -30$$

The value of G is $\boxed{-30}$.

1.3.2 Which expressions give the same answer? Why does this happen?

Which expressions give the same answer?
Expressions E and G give the same answer.

Why does this happen?
This happens because multiplication is commutative. The order in which numbers or variables are multiplied does not change the product. In expressions E ($3t(-2)$) and G ($(-2)3t$), the same factors (3, $t$, and $-2$) are being multiplied, just in a different order.

1.3.3 Expand the expressions E, F and G.

$$E = 3t(-2) = 3 \cdot (-2) \cdot t = -6t$$

The expanded expression E is $\boxed{-6t}$.

$$F = 3t(2-t) = 3t \cdot 2 - 3t \cdot t = 6t - 3t^2$$

The expanded expression F is $\boxed{6t - 3t^2}$.

$$G = (-2)3t = (-2) \cdot 3 \cdot t = -6t$$

The expanded expression G is $\boxed{-6t}$.