I have attached the question.

To calulate $\displaystyle U_1$ , I put $\displaystyle L_1$ in a matrix form as follows

1 1 2 -1

2 4 1 -1

and made that equal to the zero vector

0

0

I row reduced it with leading ones,

however I don't know what to do from there - and I certainly am not sure how the calculate the Image of $\displaystyle L_2$ either nor the others.

Hints and advice will be very much appreciated, thank you.