2x=1

x=½

5x=5

x=1

5x = 10 : 2

5x = 5

  x = 5 : 5

  x = 1

a) x = 1

b) x = 17

a)

x 2 − 2 5 = 1 10 x 2 = 1 10 + 2 5 x 2 = 1 10 + 4 10 x 2 = 1 2 ⇒ x = 1

b)

15 x − 1 3 = 28 51 15 x = 28 51 + 1 3 15 x = 28 51 + 17 51 15 x = 15 17 ⇒ x = 17

a ) x = 25 28 b ) x = 5 12 .

c) x= 1             d) x = 17

a; \(x\) - \(\dfrac{3}{4}\) = \(\dfrac{1}{7}\)

    \(x\)        = \(\dfrac{1}{7}\) + \(\dfrac{3}{4}\)

    \(x\)       =  \(\dfrac{4}{28}\) + \(\dfrac{21}{28}\)

    \(x\)       =  \(\dfrac{25}{28}\)

Vậy \(x=\dfrac{25}{28}\) 

b; - \(x\) + \(\dfrac{3}{5}\) + \(\dfrac{13}{20}\) = \(\dfrac{5}{6}\)

     (\(\dfrac{12}{20}\) + \(\dfrac{13}{20}\))  - \(x\) = \(\dfrac{5}{6}\)

    \(\dfrac{5}{4}\) - \(x\)  = \(\dfrac{5}{6}\) 

           \(x\) = \(\dfrac{5}{4}\) - \(\dfrac{5}{6}\)

           \(x\) = \(\dfrac{30}{24}\) -  \(\dfrac{20}{24}\)

            \(x\) = \(\dfrac{5}{12}\)

Vậy \(x=\dfrac{5}{4}\) 

\(A=x^{10}-14x^9-x^9+14x^8+x^8-14x^7-x^7...-x+14+1\)

\(A=x^9\left(x-14\right)-x^8\left(x-14\right)+x^7\left(x-14\right)-...-x\left(x-14\right)+1\)

\(A=1\) (Do x=14)

Ta có x=14 suy ra x+1=15

Do đó thay x+1 vào H(x), ta được:

H(14)= x¹⁰ - (x+1)x⁹ +(x+1)x⁸-(x+1)x⁷+...+ (x+1)x² - (x+1)x + x+1

H(14)= x^10 - x^10 -x^9 +x^8- x^8-x^7 +....+ x^3 +x^2 -x^2-x+x +1

Hay H(14)=1

Đặt Q(x) = x⁹ - x⁸ + x⁷ - ... + x - 1 thì (x + 1) * Q(x) = (x + 1) * (x⁹ - x⁸ + x⁷ - ... + x - 1) = x¹⁰ - 1 \(\Rightarrow\left(14+1\right)\cdot Q\left(14\right)=14^{10}-1\)

Dễ thấy: H(x) = x¹⁰ - 15* Q(x) \(\Rightarrow H\left(14\right)=14^{10}-\left(14^{10}-1\right)=1\)

Xin cậu !

ai giai giup minh minh se cho ban do mot

b, 15x - 5⁴ : 5² = 110

       15x - 5²    = 110

                15x  = 110 + 25

                 15x = 135

                    x = 135 : 15 

                    x = 9