\(\text{Tính nhanh>: 50.100+20.100+30.100}\)
Tính nhanh>:
\(\text{50.100+20.100+30.100}\)
Tìm x biết:
x.100+50.100=2500
Tính nhanh đó nha
x.100+50.100=2500
100.(x+50)=2500
x+50=2500:100
x+50=25
x=25-50
x=-25
Vậy x=-25
\(\Rightarrow100\left(x+50\right)=2500\)
\(\Rightarrow x+50=250\)
\(\Rightarrow x=200\)
\(100x+50.100=2500\)
\(\Rightarrow100x+5000=2500\)
\(100x=2500-5000\)
\(100x=-2500\)
\(\Rightarrow x=-2500:100\)
Vậy x = -25
10-(-152975)+6^90- 30.100 = ?
nó trã lời đại mà cũng li ke ngu
Bài 1 thực hiện phép tính:
a,(-1).1+(-1)^2.3+.....+(-1)^23.47+(-1)^24.49
b,(-1)^2.2+(-1)^3.4+(-1)^4.6+.......+(-1)^50.100
cho a = 1/1.21 + 1/2.22+...+1/80.100 b= 1/1.81 + 1/2.82+...+1/20.100 tính a/b
\(50.100-80+70+5+5\)
50 x 100 - 80 + 70 + 5 + 5
= 5000 - 80 + 70 + 5 + 5
= 4920 + 70 + 5 + 5
= 4990 + 5 + 5
= 4995 + 5
= 5000
< mình k bn r` mà sao bn không k mình, đồ gian >
=5000-80+70+(5+5)
=4920+70+10
=4990+10
=5000
Cho A=1/1.21+1/1.22+1/3.23+...+1/80.100
B=1/1.81+1/2.82+1/3.83+...+1/20.100
Tính A/B
A=20/1.21+20/2.22+...+20/80.100
=1-1/21+1/2-1/22+...+1/80-1/100
=(1+1/2+...+1/80)-(1/21+1/22+...+1/100)
80B=80/1.81+80/2.82+...+8/20.100
=1-1/81+1/2-1/82+...+1/20-1/100
=(1+1/2+...+1/20)-(1/81+1/82+...+1/100)
=(1+1/2+1/3+...+1/20+1/21+1/22+...+1/80)-(1/21+1/22+...1/80+1/81+1/82+...1/100)
=>20A=80B
=>A=4B
tính a/b biết a=1/1.21 + 1/2.22 + 1/3.23 + ... +1/80.100; b=1/1.81 + 1/2.82 + 1/3.82 + ... + 1/20.100
20a = 20/1.21 + 20/2.22+ ... + 20/80.100
= 1-1/21 + 1/2 - 1/22 +...+ 1/80 - 1/100
= 1 + 1/2 + 1/3 +... + 1/19 + 1/20 - 1/81 - 1/82 -.... - 1/100
80b = 80/1.81 + 80/2.82 + 80/3.83 +... + 80/20.100
= 1 - 1/81+ 1/2 - 1/83 +...+ 1/20 - 1/100
=> 20a = 80b
=> a/b = 4
Câu 24 : Cho A = 1.21 + 1/2.22 + 1/3.23 + ... + 1/80.100 ; B = 1/1.81 + 1/2.82 + 1/3.83 + ... + 1/20.100 . Tính A/B
65.142+100.15-42.65+20.100
\(65.142+100.15-42.65+20.100\)
\(=65.\left(142-42\right)+100.\left(15+20\right)\)
\(=65.100+100.35\)
\(=100.\left(65+35\right)\)
\(=100.100\)
\(=10000\)
142,742 nếu đúng thì k cho mình nha !!!
65.142+100.15-42.65+20.100
= 65 . (142 - 42) + 100 . (15 + 20)
= 65 . 100 + 100 . 35
= 100 . (65 + 35)
= 100 . 100
= 10000
Học tốt
&YOUTUBER&