Let's denote width1 with a and length1 with b. Then, the area of this room is [tex]A_{1} = a*b [/tex]
Let's denote width2 with c and length2 with d. Then, the area of the second room is [tex]A_{2} = c*d [/tex]
The total area of the rooms is [tex]A=A_{1}+A_{2}=a*b+c*d [/tex]