The expression is 

                 (Replace g, h and j with 6, 10 and 5)

To simplify the expression following order of operations to performed:

1.   Evaluate the expressions inside grouping symbols.

2.   Evaluate Powers.

3.   Multiply and/or Divide in order from left to right.

4.   Add and/or Subtract in order from left to right.

First evaluate within the parentheses.

             (Multiply:  and )

Next operation is subtraction.

                          (Subtract:  30 – 20 = 10)

Next operation is multiplication.

                              (Multiply:  )

Next operation is addition.

                                       (Add: )            

The value of the expression is 34.