Consider the area between the graphs z + y = 5 and z + 7 = y%. This area can be computed in two different ways using integrals First of all it can be computed as a sum of two integrals /abf(a:) dr + Acg(m)dm Alternatively this area can be computed as a single integral / ' h(y) dy where o = ,B= and h(y) = Either way we find that the area is _