Answer:To consolidate the given expressions, we can group like terms together.A:(-15xy) + (-9xy) = -15xy - 9xy = -24xyF:14a²b³c + (-12a²b³c) = 14a²b³c - 12a²b³c = 2a²b³cE:(-8x²y²) + (-19x²y²) = -8x²y² - 19x²y² = -27x²y²L:16nm + (-10nm⁴) = 16nm - 10nm⁴U:17abc - 6abc = 11abcG:4st + (-6ts) = 4st - 6ts = -2stT:(-xyz) + (xyz) = 0B:(-7ax²z) + 9abc = -7ax²z + 9abcR:(-abc) + 20abc - 7ax²z + 9abc = 11abc - 7ax²zE:8mn³ + (-9mn³) = 8mn³ - 9mn³ = -mn³The consolidated expressions are:A: -24xyF: 2a²b³cE: -27x²y²L: 16nm - 10nm⁴U: 11abcG: -2stT: 0B: -7ax²z + 9abcR: 11abc - 7ax²zE: -mn³Step-by-step explanation: