Simultaneous fits to four lines, from low to high frequency, p - H₂CO3_0,3−2_0,2, CH₃OH4_2,2−3_1,2, p - H₂CO3_2,2−2_2,1, and p - H₂CO3_2,1−2_2,0 for a) The Brick (ℓ = 0.241, b = 0.006, r = 25″) and b) a box centered on G0.42+0.03 (ℓ = 0.415, b = 0.032, ≈ 80″ × 80″). The fitted parameters shown in the legend are the amplitude of the H₂CO3_0,3−2_0,2 line, the centroid velocity, the line width (σ, not FWHM), the ratio R₁ = p - H₂CO S_ν(3_2,1−2_2,0) /S_ν(3_0,3−2_0,2), the ratio R₂ = p - H₂CO S_ν(3_2,2−2_2,1) /S_ν(3_2,1−2_2,0), and the amplitude of the CH₃OH4_2,2−3_1,2 line. These spectra have significantly different ratios and therefore derived temperatures: The Brick has T_G ≳ 100 K while G0.42+0.03 has T_G ≈ 40−50 K. The bottom black spectrum is the residual, and the orange wiggly spectrum shows the spline fit used to remove baseline ripples. The OCS 18–17 218.90336 GHz and HC₃N 24–23 218.32471 GHz lines are also detected, but not fitted, in The Brick. In these examples, we are showing cases where the CH₃OH4_2,2−3_1,2 and p - H₂CO3_2,2−2_2,1 lines are not too badly blended, but along many lines of sight, especially those within ~20′ of Sgr B2, they are irretrievably blended.