According to the first law of thermodynamics, the increase in the internal energy during any process involving a gas:

equals the heat input minus the work done on the gas

is independent of the work done on the gas

is independent of the heat input equals

the heat input plus the work done on the gas

equals the work done on the gas minus the heat input

heat input minus the work done on the gas.

Explanation:

According to the first law of thermodynamics, the increase in the internal energy during any process involving a gas equals to the heat input minus the work done on the gas.

we know that from the First law for process

heat input = change in internal energy + work done

dQ = dU + dW

this implies

dU = dQ - dW

So we write the above statement