\(\dfrac{2}{4\times6}+\dfrac{2}{6\times8}+...+\dfrac{2}{188\times190}\\ =\dfrac{1}{4}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{8}+....+\dfrac{1}{188}-\dfrac{1}{190}\\ =\dfrac{1}{4}-\dfrac{1}{190}\\ =\dfrac{93}{380}\)

\(\dfrac{2}{4\times6}+\dfrac{2}{6\times8}+...+\dfrac{2}{188\times190}\)

\(=\dfrac{1}{4}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{8}+...+\dfrac{1}{188}-\dfrac{1}{190}\)

\(=\dfrac{1}{4}-\dfrac{1}{190}\)

\(=\dfrac{190-4}{760}\)

\(=\dfrac{186}{760}=\dfrac{93}{380}\)

\(a,1999-2000+1=\left(1999+1\right)-2000=2000-2000=0\\ b,450:5+550:5=\left(450+550\right):5=1000:5=200\\ c,188\times7+188\times4-188=188\times\left(7+4-1\right)=188\times10=1880\)

a,1999−2000+1=(1999+1)−2000=2000−2000=0b,450:5+550:5=(450+550):5=1000:5=200c,188×7+188×4−188=188×(7+4−1)=188×10=1880

a) 1999 - 2000 + 1

= ( 1999 + 1 ) - 2000

= 2000 - 2000

= 0

b) 450 : 5 + 550 : 5

= ( 450 + 550 ) : 5 

= 1000 : 5

= 200

c) 188 x 7 + 188 x 4 - 188

= ( 7 + 4 - 1 ) x 188

= 10 x 188

= 1880

\(A.3^x+37=188\)

\(\Rightarrow3^x=188-37\)

\(\Rightarrow3^x=151\)

\(\Rightarrow x\in\varnothing\)

\(B.\left(x-2\right)5-5=5\)

\(\Rightarrow5x-10=5+5\)

\(\Rightarrow5x=10+10\)

\(\Rightarrow x=20\div5=4\)

3^x=188-37

3^x=151=....... sai đề 

(x-2).5-5=5

(x-2).5=10

(x-2)=2

x=4

a) 3^x + 37 = 188

=> 3^x = 151

Làm đến đoạn này là thấy sai đề òi :))

b) ( x - 2 ) . 5 - 5 = 5

=> ( x - 2 ) . 5 = 10

=> x - 2 = 50

=> x = 52

Hơi tắt một xíu :))

Trả lời :

188 - 2x = 84

=> 2x = 104

=> x = 52

188 - 2X = 84 

          2X = 188 - 84 

          2X = 104 

            X = 104 : 2 

             X = 52 

CHÚC bạn học tốt 

188 - 2x = 84

         2x = 188 - 84

        2x  = 104

          x  = 104 : 2

          x  = 52

Học Tốt !

150 - xx5 + 18 = 188 đúng ko ạ?

10

Cho mình xin cách lm ạ

Cách lm

 600 : x + 128 = 188

x                     = 600 : 188

x                     = ?

x                     = ? - 128

x                     = ?

600 : 60 = 10

b)\(=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+...+\frac{1}{188}-\frac{1}{190}\)

\(=\frac{1}{2}-\frac{1}{190}\)

\(=\frac{47}{95}\)