x+1/3 = 3/4

=> x = 3/4 - 1/3

x = 5/12

-x-2/3 = 6/7

=> -x = 6/7 + 2/3

-x   = 32/21

x = -32/21

a) \(x+\frac{1}{3}=\frac{3}{4}\Rightarrow x=\frac{3}{4}-\frac{1}{3}\Rightarrow x=\frac{5}{12}\)

b) \(-x-\frac{2}{3}=\frac{6}{7}\Rightarrow-x=\frac{6}{7}+\frac{2}{3}\Rightarrow-x=\frac{32}{21}\Rightarrow x=-\frac{32}{21}\)

Ta có : ( x+1 ) + ( x + 2 ) + ( x + 3 ) + ( x + 4 ) + ( x + 5 ) = 30

            ( x + x + x +x +x ) + ( 1 + 2 + 3 + 4 + 5 ) = 30

             x * 5 + 15 = 30

              x * 5 = 30 - 15

              x * 5 = 15

                   x = 15 : 5 

                  x = 3

Vậy x = 3

Duyệt đi , chúc bạn học giỏi

(x + 1) + (x + 2) + (x + 3) + (x + 4) + (x + 5) = 4 + 5 + 6 + 7 + 8

x + 1 + x + 2 + x + 3 + x + 4 + x + 5 = 30

\(x\)x 5  + 15 = 30

\(x\)x 5 = 30 - 15 = 15

x = 15 : 5 = 3

BẠN VÀO CÂU HỎI TƯƠNG TỰ RỒI TÌM .

segerheth

gfjxdddddddddrjxdjmnx

=>1/3 - 1/7=1/x

\(\frac{5}{3}-\frac{1}{3}:\left(1-x\cdot\frac{1}{3}\right)=\frac{7}{6}\)

=> \(\frac{1}{3}:\left(1-x\cdot\frac{1}{3}\right)=\frac{5}{3}-\frac{7}{6}\)

=> \(\frac{1}{3}:\left(1-x\cdot\frac{1}{3}\right)=\frac{1}{2}\)

=> \(\left(1-x\cdot\frac{1}{3}\right)=\frac{1}{3}:\frac{1}{2}=\frac{1}{3}\cdot2=\frac{2}{3}\)

=> \(1-\frac{x}{3}=\frac{2}{3}\)

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

=> x = 1

\(3-\left(x:\frac{1}{2}+\frac{3}{2}\right)-\frac{1}{4}=\frac{1}{2}\)

=> \(3-\left(x:\frac{1}{2}+\frac{3}{2}\right)=\frac{1}{2}+\frac{1}{4}=\frac{3}{4}\)

=> \(x:\frac{1}{2}+\frac{3}{2}=3-\frac{3}{4}=\frac{9}{4}\)

=> \(x:\frac{1}{2}=\frac{9}{4}-\frac{3}{2}\)

=> \(x:\frac{1}{2}=\frac{3}{4}\)

=> \(x=\frac{3}{4}\cdot\frac{1}{2}=\frac{3}{8}\)

\(\frac{5}{3}-\frac{1}{3}:\left(1-x\times\frac{1}{3}\right)=\frac{7}{6}\)

\(\frac{1}{3}:\left(1-x\times\frac{1}{3}\right)=\frac{5}{3}-\frac{7}{6}\)

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

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

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

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

\(x\times\frac{1}{3}=\frac{1}{3}\)

\(x=\frac{1}{3}:\frac{1}{3}\)

\(x=1\)

\(3-\left(x:\frac{1}{2}+\frac{3}{2}\right)-\frac{1}{4}=\frac{1}{2}\)

\(3-\left(x:\frac{1}{2}+\frac{3}{2}\right)=\frac{1}{2}+\frac{1}{4}\)

\(3-\left(x:\frac{1}{2}+\frac{3}{2}\right)=\frac{3}{4}\)

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

\(x:\frac{1}{2}+\frac{3}{2}=\frac{9}{4}\)

\(x:\frac{1}{2}=\frac{9}{4}-\frac{3}{2}\)

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

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

\(x=\frac{3}{8}\)

a) \(\frac{3}{2}x-\frac{2}{5}=\frac{1}{3}x-\frac{1}{4}\)

\(\Rightarrow\frac{3}{2}x-\frac{1}{3}x=-\frac{1}{4}+\frac{2}{5}\)

\(\frac{7}{6}x=\frac{3}{20}\Rightarrow x=\frac{9}{70}\)

b) \(-5^{\frac{1}{2}x+1}=\frac{3}{4}-\frac{7}{6}\)

\(-5^{\frac{1}{2}x}.\left(-5\right)=-\frac{5}{12}\)

\(-5^{\frac{1}{2}x}=\frac{1}{12}\)

mà -5^1/2x mang giá trị âm

1/12 có giá trị dương

=> không tìm được x

c) \(\frac{2x-2}{3}=\frac{7x+3}{2-1}\)

\(\frac{2x-2}{3}=7x+3=\frac{21x+9}{3}\)

=> 2x - 2 = 21x + 9

=> 2x - 21x = 9 + 2

-19x = 11

x = -11/19

phần d bn lm như phần a nha

a) 75% x X+ 3/4 = 30

              75%x X= 30-3/4

              75%x X=117/4

                        X=117/4 : 75/100

                        X=117/4 x 100/75

                        X= 39