1, tính nhanh
a, 36.28+36.82+64.69+64.41
B, 13,5.5,8-8,3.4,2-5,8.8,3+4,2.14,5
C, 4,8.13,3+4,8.6,7+5,2.13,3+5,2.6,7
D, 7,8.55,1+92,2.55,1-7,8.5,1-99,2.5,1
E, 85.12,7+5.3.12,7
F, 52.143-52.39-8.26
G, 13.49+18.49-25.49+49.7
2, tìm x
(6x+11)(5y-12)-42x+66=0