Yes "3x8 = 4x6" does illustrate the commutative property of multiplication.
Slope = 2/3 (positive 2/3)
You use the formula Y2-Y1/X2-X1 in order to get the slope
Yes it is, 6.52 and 6.52 are the same but one has an extra 0.
217.5/87=2.5. I put it into a calculator and this is what I got.