2^x.(3+2^3)=44

2^x.11=44

2^x=44:11

2^x=4=2^2

=> x=2

k mk nha

1 ) x = 0,375

2) x= 7,530514717

nhoc oi tra loi han hoi ra

a) \(2^{3x+2}=4^{x+5}\Leftrightarrow2^{3x+2}=2^{2\left(x+5\right)}\Leftrightarrow2^{3x+2}=2^{2x+10}\)

\(\Rightarrow3x+2=2x+10\Leftrightarrow3x+2-2x-10\)

\(\Leftrightarrow x-8=0\Leftrightarrow x=8\) vậy \(x=8\)

câu : b ; c mk cảm thấy đề sai

\(\frac{1}{3}x+\frac{2}{5}\left(x-1\right)=0\)

\(\Leftrightarrow\frac{1}{3}x+\frac{2}{5}x-\frac{2}{5}=0\)

\(\Leftrightarrow\frac{1}{3}x+\frac{2}{5}x=0+\frac{2}{5}\)

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

\(\Leftrightarrow x\left(\frac{5}{15}+\frac{6}{15}\right)=\frac{2}{5}\)

\(\Leftrightarrow\frac{11}{15}x=\frac{2}{5}\)

\(\Leftrightarrow x=\frac{2}{5}\div\frac{11}{15}\)

\(\Leftrightarrow x=\frac{6}{11}\)

\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\left(x+1\right)}=\frac{49}{50}\)

\(\Leftrightarrow\frac{2}{6}+\frac{2}{12}+\frac{2}{20}+...+\frac{2}{x\left(x+1\right)}=\frac{49}{50}\)

\(\Leftrightarrow2\left(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{x\left(x+1\right)}\right)=\frac{49}{50}\)

\(\Leftrightarrow2\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{x}-\frac{1}{x+1}\right)=\frac{49}{50}\)

\(\Leftrightarrow2\left(\frac{1}{2}-\frac{1}{x+1}\right)=\frac{49}{50}\)

\(\Leftrightarrow\frac{1}{2}-\frac{1}{x+1}=\frac{49}{50}\div2\)

\(\Leftrightarrow\frac{1}{2}-\frac{1}{x+1}=\frac{49}{50}\times\frac{1}{2}\)

\(\Leftrightarrow\frac{1}{2}-\frac{1}{x+1}=\frac{49}{100}\)

\(\Leftrightarrow\frac{1}{x+1}=\frac{1}{2}-\frac{49}{100}\)

\(\Leftrightarrow\frac{1}{x+1}=\frac{50}{100}-\frac{49}{100}\)

\(\Leftrightarrow\frac{1}{x+1}=\frac{1}{100}\)

\(\Leftrightarrow x+1=100\)

\(\Leftrightarrow x=100-1\)

\(\Leftrightarrow x=99\)

a) 2x - 138 = 3² . 2³ 

    2x - 138 = 72

              2x = 72 + 138

              2x = 210

               x = 105

b) 6x - 39 = 588 : 28 

    6x - 39 = 21

           6x = 21 + 39

           6x = 60

             x = 60 : 6 = 10

c)42 . x + 37 . 42 = 39 . 42

       42 . (x + 37) = 1638

                x + 37 = 1638 : 42

                x + 37 = 39

                        x = 39 - 37

                        x = 2

câu 1 x^2 +3x=xx+3x=x(x+3) vì x+3 chia hết cho x+3 nên x(x+3) chia hết cho x+3 hay x^2+3x chia hết cho x+3