a)

\(3:\left(\dfrac{9}{4}\right)=\dfrac{3}{4}:\left(6.x\right)\\ \Rightarrow3.6.x=\dfrac{3}{4}.\dfrac{9}{4}\\ x=\dfrac{3}{4}.\dfrac{9}{4}.\dfrac{1}{3}.\dfrac{1}{6}\\ x=\dfrac{3}{4.4.2}\\ x=\dfrac{3}{32}\)

b)

\(4,5:0,3=\left(5.0,09\right):\left(0,01.x\right)\\ 0,01.x.4,5=5.0,09.0,3\\ x=5.\dfrac{9}{100}.\dfrac{3}{10}.100.\dfrac{10}{45}\\ x=3\)

d)

\(\left(\dfrac{1}{9}.x\right)=\dfrac{7}{4}:\dfrac{2}{25}\\ \left(\dfrac{1}{9}.x\right)=\dfrac{7}{4}.\dfrac{25}{2}\\ x:\dfrac{7}{4}=\dfrac{25}{2}:\dfrac{1}{9}\\ x=\dfrac{25}{2}.9.\dfrac{7}{4}\\ x=\dfrac{1575}{8}\\ x=196\dfrac{7}{8}\)

e)

\(\dfrac{-2}{x}=\dfrac{-x}{\dfrac{8}{25}}\\ -x.x=-2.\dfrac{8}{25}\\ -x^2=-\dfrac{16}{25}=-\dfrac{4^2}{5^2}\\ -x^2=-\left(\dfrac{4}{5}\right)^2\\ \Rightarrow x=\dfrac{4}{5}\)

Chúc bạn học tốt

\(\left(x+\frac{3}{5}\right)^2+1\frac{16}{25}=9\%:4,5\%\)

\(\left(x+\frac{3}{5}\right)^2+1\frac{16}{25}=2\)

\(\left(x+\frac{3}{5}\right)^2=2-1\frac{16}{25}\)

\(\left(x+\frac{3}{5}\right)^2=\frac{9}{25}=\frac{3}{5}^2\)

\(x+\frac{3}{5}=\frac{3}{5}\)

\(x=\frac{3}{5}-\frac{3}{5}\)

\(x=0\)

\(\left(x+\frac{3}{5}\right)^2+1\frac{16}{25}=9\%:4,5\%\)

\(\left(x+\frac{3}{5}\right)^2+1\frac{16}{25}=2\)

\(\left(x+\frac{3}{5}\right)^2=2-1\frac{16}{25}\)

\(\left(x-\frac{3}{5}\right)^2=\frac{3^2}{5}\)

\(x=\frac{3}{5}-\frac{3}{5}\)

\(x=0\)

b,

= (4,5 x16 - 1,7) : (4,5 x 15 - 1,7)

= 1

c,

= ( 82 - 82 ) : 36 x ( 32 + 17 + 99 - 81 + 1 )

= 0 : 36 x ( 32 + 17 + 99 - 81 + 1 )

= 0 x ( 32 + 17 + 99 - 81 + 1 )

= 0

d,

= (30 : 7,5 + 0,5 x 3 - 1,5) x (4,5 - 4,5)

= (30 : 7,5 + 0,5 x 3 - 1,5) x 0

= 0

đề bài là j e nhở? 

(x + \(\dfrac{3}{5}\))² + 1\(\dfrac{16}{25}=9\%:4,5\%\)
<=> x² + (\(\dfrac{3}{5}\))² + 1\(\dfrac{16}{25}=2\)
<=> x² + \(\dfrac{9}{25}+\dfrac{41}{25}=2\)
<=> x² + 2 = 2
<=> x² = 0
<=> x = 0
@Khánh Linh

a) 58 × 75 + 58 × 50 - 58 × 25

= 58 x ( 75 + 50 - 25 )

= 58 x 100 = 5800

b) 13,6 + 14,5 + 15,4 - 4,5 - 3,6 - 5,4

= ( 13,6 - 3.6 ) + ( 14,5 - 4,5 ) + ( 15,4 - 5,4 )

= 10 + 10 + 10 = 30

c) Bạn ghi sai đề. Sửa lại.

 0,2 x 17 x 9 + 0,18 x 540 + 29 x 1,8

= 1,8 x 17 + 1,8 x 540 : 10 + 29 x 1,8

= 1,8 x ( 17 + 54 + 29 )

= 1,8 x 100 = 180

d) 5 + 8 + 11 + 14 +...... + 41

Số số hạng:

( 41 - 5 ) : 3 + 1 = 13 ( số )

S = ( 5 + 41 ) x 13 : 2 = 299

giúp câu cuối nha =w=

d) 5 + 8 + 11 + 14 + ....... + 41

Số số hạng là : ( 41 - 5 ) : 3 + 1 = 13 ( số )

Tổng là : ( 41 + 5 ) x 13 : 2 = 299

1. 

a) \(\frac{13}{8}:\frac{13}{4}=\frac{1}{2}=0,5=50\%\)

b) \(12,5:2,5=5=500\%\)

~ Hok tốt ~

2.

\(\left(\frac{37}{9}+\frac{13}{4}\right).\frac{9}{4}+\frac{11}{4}\)

\(=\frac{265}{36}.\frac{9}{4}+\frac{11}{4}\)

\(=\frac{265}{16}+\frac{11}{4}\)

\(=\frac{309}{16}\)

\(1+\left(\frac{9}{10}-\frac{4}{5}\right):\frac{19}{6}\)

\(=1+\frac{1}{10}:\frac{19}{6}\)

\(=1+\frac{3}{95}\)

\(=\frac{98}{95}\)

\(\left(-7+\left|13\right|\right)-\left(13-\left|-7\right|-25\right)-\left(25+\left|-10\right|-9\right)\)

\(=\left(-7+13\right)-\left(13-7-25\right)-\left(25+10-9\right)\)

\(=-7+13-13+7+25-25-10+9\)

\(=\left(-7+7\right)+\left(13-13\right)+\left(25-25\right)-10+9\)

\(=0+0+0-10+9\)

\(=-10+9\)

\(=-1\)

~ Hok tốt ~

3.

\(2x+\frac{1}{4}=\frac{3}{2}\)

\(2x=\frac{3}{2}-\frac{1}{4}\)

\(2x=\frac{5}{4}\)

\(x=\frac{5}{4}:2\)

\(x=\frac{5}{8}\)

\(\left(x-5\right)-\frac{1}{3}=\frac{2}{5}\)

\(x-5=\frac{2}{5}+\frac{1}{3}\)

\(x-5=\frac{11}{15}\)

\(x=\frac{11}{15}+5\)

\(x=\frac{86}{15}\)

\(\left(4,5-2x\right):\frac{3}{4}=\frac{4}{3}\)

\(\left(\frac{9}{2}-2x\right):\frac{3}{4}=\frac{4}{3}\)

\(\frac{9}{2}-2x=\frac{4}{3}.\frac{3}{4}\)

\(\frac{9}{2}-2x=1\)

\(2x=\frac{9}{2}-1\)

\(2x=\frac{7}{2}\)

\(x=\frac{7}{2}:2\)

\(x=\frac{7}{4}\)

~ Hok tốt ~

Tìm x thuoc z:

1) \(26-\left|x+9\right|=-13\)

\(\Leftrightarrow\left|x+9\right|=26-\left(-13\right)\)

\(\Leftrightarrow\left|x+9\right|=39\)

\(\Leftrightarrow\left[{}\begin{matrix}x+9=39\\x+9=-39\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=39-9=30\\x=-39-9=-48\end{matrix}\right.\)

Vậy: \(x\in\left\{30;-48\right\}\)

2) \(\left|x+7\right|-13=25\)

\(\Leftrightarrow\left|x+7\right|=25+13=38\)

\(\Leftrightarrow x+7\in\left\{38;-38\right\}\)

\(\Leftrightarrow x\in\left\{31;-45\right\}\)

Vậy:.................

tim x biet

\(1)123-3.\left(x+4\right)=23\)

\(\Leftrightarrow3\left(x+4\right)=123-23\)

\(\Leftrightarrow3\left(x+4\right)=100\)

\(\Leftrightarrow x+4=\frac{100}{3}\)

\(\Leftrightarrow x=\frac{100}{3}-4=\frac{100-12}{3}=\frac{88}{3}\)

Vậy:................

2) Tương tự