a)A=1.1189

b)B=1/21/68

a, \(1+\dfrac{3}{4}=\dfrac{7}{4}\)

b, \(\dfrac{4}{5}-\dfrac{3}{8}=\dfrac{32-15}{40}=\dfrac{17}{40}\)

c, \(1:\dfrac{2}{3}=\dfrac{1.3}{2}=\dfrac{3}{2}\)

d, \(\dfrac{2}{5}.\dfrac{5}{2}=1\)

a)1 + 3/4=7/4

   b)4/5 -3/8=17/40

  c)1 : 2/3=3/2

  d)2/5 x 5/2=1

Đáp án:

a)1 + 3/4=7/4

b)4/5 -3/8=17/40

c)1 : 2/3=3/2

d)2/5 x 5/2=1

a.5/14+1/2=6/7

b.5/3-1=2/3

c.4/3-1/3=1

a) 5/14+ 1/2= 6/7

b) 5/3 - 1= 2/3

c) 4/3- 1/3 =1

a.5/14+1/2=6/7

b.5/3-1=2/3

c.4/3-1/3=1

?

\(A=\dfrac{x^3}{9y^2}-\dfrac{1}{8}x^2y+\dfrac{2}{15}xy^2\\ B=\dfrac{2a-b}{a+1}-\dfrac{\left(a-1\right)^2}{b-2}\cdot\dfrac{\left(b-2\right)\left(b+2\right)}{\left(a-1\right)\left(a+1\right)}\\ B=\dfrac{2a-b}{a+1}-\dfrac{\left(a-1\right)\left(b+2\right)}{a+1}\\ B=\dfrac{2a-b-\left(a-1\right)\left(b+2\right)}{a+1}\\ B=\dfrac{2a-b-ab-2a+b+2}{a+1}=\dfrac{2-ab}{a+1}\)

\(\dfrac{3}{2}x+\dfrac{3}{7}=-\dfrac{4}{5}\)

\(\Leftrightarrow\dfrac{3}{2}x=-\dfrac{43}{35}\)

\(\Leftrightarrow x=-\dfrac{86}{105}\)

Vậy \(x=-\dfrac{86}{105}\)

\(-\dfrac{11}{12}x+0,25=\dfrac{5}{6}\)

\(\Leftrightarrow-\dfrac{11}{12}x+\dfrac{1}{4}=\dfrac{5}{6}\)

\(\Leftrightarrow-\dfrac{11}{12}x=\dfrac{7}{12}\)

\(\Leftrightarrow x=-\dfrac{7}{11}\)

Vậy \(x=-\dfrac{7}{11}\)

\(\left(x-2\right)^2=1\)

\(\Leftrightarrow\left(x-2\right)^2-1=0\)

\(\Leftrightarrow\left(x-2-1\right)\left(x-2+1\right)=0\)

\(\Leftrightarrow\left(x-3\right)\left(x-1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\x-1=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)

Vậy x = {3; 1}\(\left(2x-1\right)^3=-8\)

\(\Leftrightarrow2x-1=-2\)

\(\Leftrightarrow2x=-1\)

\(\Leftrightarrow x=-\dfrac{1}{2}\)

Vậy \(x=-\dfrac{1}{2}\)

       (x - 2)² = 1

<=>\(\left[{}\begin{matrix}x-2=1\\x-2=-1\end{matrix}\right.< =>\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)

Vậy x = 3; 1

(2x - 1)³ = -8

<=> 2x - 1 = -2

<=> 2x = -1

<=> x = \(\dfrac{-1}{2}\)

Vậy x = \(\dfrac{-1}{2}\)

\(|\) 2,5 - x\(|\) = 1,3

1,6- \(|\)x - 0,2 \(|\)= 0

13^x = 169

\(\dfrac{-2}{x}\)=\(\dfrac{-x}{8\dfrac{ }{25}}\)

\(\dfrac{x}{-15}\)=\(\dfrac{-60}{x}\)

\(|\)x\(|\)+0,573=2

=1,4 x\(\dfrac{15}{49}-\) \(\left(\dfrac{4}{5}+\dfrac{2}{3}\right)\) : 2\(\dfrac{1}{5}\)

=  \(\dfrac{3}{7}\) - \(\dfrac{22}{15}\) : \(\dfrac{11}{5}\)

= \(\dfrac{3}{7}\) -  \(\dfrac{2}{3}\)

= \(-\dfrac{5}{21}\) 

( 2\(\dfrac{1}{5}\) + \(\dfrac{3}{5}\) \(\times\) \(x\)) = \(\dfrac{3}{4}\)

  \(\dfrac{11}{5}\) + \(\dfrac{3}{5}\)\(x\) = \(\dfrac{3}{4}\)

            \(\dfrac{3}{5}\)\(x\) = \(\dfrac{3}{4}\) - \(\dfrac{11}{5}\)

           \(\dfrac{3}{5}\)\(x\) = - \(\dfrac{29}{20}\)

             \(x\) = -\(\dfrac{29}{12}\)

3\(\dfrac{1}{3}\) x \(x+16\)\(\dfrac{3}{4}\)= 13,25

\(\dfrac{10}{3}\) x \(x\) + \(\dfrac{67}{4}\) = 13,25

\(\dfrac{10}{3}\) x \(x\) = 13,25 - \(\dfrac{67}{4}\)

\(\dfrac{10}{3}\times x=\) \(\dfrac{103}{28}\) 

          \(x\) = \(\dfrac{103}{28}:\dfrac{10}{3}\)

          \(x=\) \(\dfrac{309}{280}\)

Cần chi tiết hum bẹn

a) = 76/35 ; 37/9

b) 143/40 ; 19/15

c) 2/3 ; 42/5

d) 21/4 ; 4/7 

a, 11/7 + 3/5

= \(\dfrac{11x5}{7x5}+\dfrac{3x7}{5x7}=\dfrac{55}{35}+\dfrac{21}{35}=\dfrac{76}{35}\)

4 + 1/9

= \(\dfrac{4}{1}+\dfrac{1}{9}=\dfrac{4x9}{1x9}+\dfrac{1x1}{9x1}=\dfrac{36}{9}+\dfrac{1}{9}=\dfrac{37}{9}\)

b, 21/5 - 5/8

= \(\dfrac{21x8}{5x8}-\dfrac{5x5}{8x5}=\dfrac{168}{40}-\dfrac{25}{40}=\dfrac{143}{40}\)

2 - 11/15

=\(\dfrac{2}{1}-\dfrac{11}{15}=\dfrac{30}{15}-\dfrac{11}{15}=\dfrac{19}{15}\)

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