[Solved] How to align the left parts in 2-nd and 4th lines?

Nick Asks: How to align the left parts in 2-nd and 4th lines?
I need to aling the 2nd and 4th lines in the case:

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I have tried to use the & sign in different places of the code:

    f(t) =
                         D, &Delta P_i(t) leq -E, \ 
                         d, quad -E < &Delta P_i(t) leq 0 , \
                         e, &Delta P_i(t) = 0 , \
                         r, quad 0 < &Delta P_i(t)leq  E, \
                         R, & Delta P_i(t) >E, \

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