xem lại đề hộ mk nhé 

mk sửa đề thế này 

x+ ( x+1)+(x+2)+....+(x+24)+(x+25) = 25 

=> x+ x+1 + x + 2 +...+ x+ 24 + x + 25 = 25 

=> 25x + 325 = 25 

từ đây tính ra x

doi 25%=25/100=1/4

x=1/2+1/4*x

x=1/2+1/4

x=6/8=3/4

nho ****

\(\left(x+1\right)+\left(x+2\right)+...+\left(x+10\right)=25\)

\(\Rightarrow\left(x+x+...+x\right)+\left(1+2+...+10\right)=25\)

\(\Rightarrow10x+105=25\)

\(\Rightarrow10x=-80\)

\(\Rightarrow x=-8\)

Vậy x = -8

(x + 1) + (x + 2) + ... + (x + 9) + (x + 10) = 25

          x + 1 + x + 2 + ... + x + 9 + x + 10 = 25

                     10x + (1 + 2 + ... + 9 + 10) = 25

                                                10x + 55 = 25

                                                        10x = 25 - 55

                                                         10x = -30

                                                             x = -3

a)  4^x = 64

     4^x =  4³

=> x = 3

c)   5^x+2 = 25

      5^x+2 = 5²

=> x + 2 = 2

=>        x = 0

mình thấy phần b hình như sai đề

Có:

a)\(4^x=64=4^3=>x=3\)

b)\(2^{x+1}=25=>2^x.2=25\Rightarrow2^x=25:2=12,5\)

=> ....

c)\(5^{x+2}=25\Rightarrow5^x.5^2=25=>5^x.25=25=>5^x=25:25=1\)

=>x=0

x + 25%x = \(\frac{1}{2}\)

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

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

x . \(\frac{5}{4}\)= \(\frac{1}{2}\)

x       = \(\frac{1}{2}\div\frac{5}{4}\) 

x       = \(\frac{2}{5}\)

Ta có : \(X+25\%.X=\frac{1}{2}\Leftrightarrow X+\frac{1}{4}.X=\frac{1}{2}\Leftrightarrow X.\left(1+\frac{1}{4}\right)=\frac{1}{2}\)\(\Leftrightarrow X.\frac{5}{4}=\frac{1}{2}\Leftrightarrow X=\frac{1}{2}:\frac{5}{4}\Leftrightarrow X=\frac{2}{5}\)

x+1/2.x - 25%.x = x.(1+1/2-25%) = x.1,25 = 10 => x = 10 : 1,25 = 8

\(x-25\%.x=\frac{1}{2}\)

\(x.1-25\%.x=\frac{1}{2}\)

\(x.\left(1-25\%\right)=\frac{1}{2}\)

\(x.\left(1-\frac{1}{4}\right)=\frac{1}{2}\)

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

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

\(x=\frac{2}{3}\)

a, 11 - ( 15 + 11 ) = x - ( 25 - 9 )

11-15-11=x-25+9

-15=x-16

x=1

b, 2 - x = 17 - ( - 5 )

2-x=22

x=-20

c, x - 12 = ( - 9 ) - 15

x-12=-24

x=-12

d, 9 - 25 = ( 7 - x ) - ( 25 + 7 )

(7-x)-32=-16

7-x=16

x=-9

#H