The mathematical calculation problem of Beijing Normal University edition should be pure calculation, not solving equations, as long as simplifying the evaluation, merging similar items and removing brackets Urgent, 10 more points before 20:00 on November 20

The mathematical calculation problem of Beijing Normal University edition should be pure calculation, not solving equations, as long as simplifying the evaluation, merging similar items and removing brackets Urgent, 10 more points before 20:00 on November 20

Merge the similar items: (1) 3x2-1-2x-5 + 3x-x2; (2) - 0.8a2b-6ab-1.2a2b + 5ab + A2B; (3) 6x2y + 2xy-3x2y2-7x-5yx-4y2x2-6x2y (5) 4x2y-8xy2 + 7-4x2y + 12xy2-4; (6) a2-2ab + B2 + 2A2 + 2Ab - B2.1, (- 7) - (- 8) + (- 2) - (- 12) + (- 3) 2, (- 6.3) - (...)