Enzyme Kinetics two enzymes in complex with one substrate
As this seems like a homework question (and may be closed), as an example consider the reaction  $\ce{H2 + I2 = 2HI}$. The rate, r is $\displaystyle r=\frac{1}{2}\frac{d\mathrm{[HI]}}{dt}=k_1\mathrm{[H_2][I_2]}-k_2\mathrm{[HI]}^2$ where the rate constants $k_1,\;k_2$ are for the forward and reverse reactions respectively. (This assumes that the reaction occurs as written.) As   steady state the intermediate or transient species has a rate of change of zero and you note in your question.

In the general case if the reaction is $aA+bB= dD+eE$ then $\displaystyle -\frac{1}{a}\frac{d[A]}{dt}=-\frac{1}{b}\frac{d[B]}{dt}=\frac{1}{d}\frac{d[D]}{dt}=-\frac{1}{e}\frac{d[E]}{dt}$