The expression would be...
(4 x 7) x 2
The way you would calculate this expression would be like this...
you see that the 4 and 7 are in the parentheses (4 x 7) and parentheses means that whatever the number is in it, has to be done first. It is written in the order of operations.
After...
So the next step is take the product of 4 x 7 which is 28, and double it. What does double it mean? It means that you multiply that number by 2.
So 28 x 2 = 56
So The Answer...
So our answer would be (4 x 7) x 2 = 56
Hope I helped :)