165-(1/3+2/5)=?
Thực hiện phép tính sau:
a) 12.32+5.43 - 42.22
b) 57:53+35.3
c)53.3+ [ 85 - ( 11 -6 )2 ]
d) 165 . 15 + 165 . 35 + 165 . 50
Tinh nhanh
5/11+1/2+2/5+6/11+3/4+16/25+5/16
1313/2121+165/165/424242/151515
1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256
Tính tổng S=1/30+2/48+3/88+4/165+5/300
Ta có: \(S=\frac{1}{5.6}+\frac{2}{6.8}+\frac{3}{8.11}+\frac{4}{11.15}+\frac{5}{15.20}\)
\(\Rightarrow S=\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+....+\frac{1}{15}-\frac{1}{20}\)
\(=\frac{1}{5}-\frac{1}{20}=\frac{4}{20}-\frac{1}{20}=\frac{3}{20}\)
tim x
1/5 + 2/30 + 121/165 < hoặc = x < hoặc = 1/2 + 156/72 + 1/3
Tìm x biết
a. (3.x + 2 ) . ( x + 1 ) = 140
b. ( 2.x + 3 ) . ( x+5 ) = 165
1 + 3 + 5 +.... + x = 165
Tham khảo:
cho .... là x
=>1+3+5+x+x=165
=>9+x+x=165
=>9+2x=165
=>2x=165−9
=>2x=156
=>x=78
(x-1/2)^2=4/9
5^x-3=165
/x+1/+/y+5/=0
ko giải theo phương trình nhé ^-^
a) 165-(35:x+3)*15=15
b) (1*3/10-x):(19/10-1-2/5)+4/5=1
giúp mk giải câu này nhé!!!
a) => (35:x+3)*15 = 165-15=150
=> 35:x+3 = 150:15=10
=> 35:x = 10-3 = 7
=> x = 35:7 = 5
b) => 1*3/10x :1/2 +4/5 =1
=> 1*3/10x:1/2 =1-4/5=1/5
=> 1*3/10x = 1/5 *1/2 =1/10
=> 3/10-x = 1/10
=> x = 3/10 - 1/10 = 2/10 = 1/5
Tim x biet
A, 5/9 + x/-1 = -1/3
B, 1/5 + 2/20 + 121/165 <x< 1/2 + 156/72 + 1/3 ( x thuoc N)
C, x + 5/3 = 1/81
D, x-1/3 + 3x-5/2 + 2x/9 + -5x+3/9 = 210/420
a: -x+5/9=-1/3
nên x=5/9+1/3=5/9+3/9=8/9
b: \(\Leftrightarrow\dfrac{1}{5}+\dfrac{1}{10}+\dfrac{11}{15}< x< \dfrac{1}{2}+\dfrac{13}{12}+\dfrac{1}{3}\)
=>31/30<x<23/12
mà x là số nguyên
nên \(x\in\varnothing\)
c: x+5/3=1/81
nên x=1/81-135/81=-134/81