Đáp án:
a)
25.27.4
=25.4.27
=100.27
=2700
b)
63+118+37+82
=63+37+118+82
=100+200
=300
Câu 3:
2(x+25)=60
x+25=60:2
x+25=30
x=30-25
x=5
b) 12x-33=3^2018:3^2017
12x-33=3^1
12x-33=3
12x=3+33
12x=36
x=36:12
x=3
c) 1.2.3....7.8^2 + 1.2.3...8-1.2.3...9
= (1.2.3...7.8).8 + 1.2.3...7.8-(1.2.3...7.8).9
= (1.2.3...7.8).(8+1-9)
= (1.2.3...7.8).0
=0
Xin ctlhn ạ!!!
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