Question

Tìm x . 

x(x-5).(x+5)-(x+2).(x^2-2x+4)=17

Mình cần giải thích cặn kẽ ạ ! Cần gấp lắm ạ .

Cảm ơn .

Answer 1

x(x-5).(x+5)-(x+2).(x^2-2x+4)=17

\(\Leftrightarrow x\left(x^2-25\right)-\left(x^3-2x^2+4x+2x^2-4x+8\right)=17\)

\(\Leftrightarrow x^3-25x-x^3+2x^2-4x-2x^2+4x-8=17\)

\(\Leftrightarrow-25x=17+8\)

\(\Leftrightarrow-25x=25\)

\(\Leftrightarrow x=-1\)

Answer 2

#)Giải :

\(x\left(x-5\right)\left(x+5\right)-\left(x+2\right)\left(x^2-2x+4\right)=17\)

\(\Rightarrow x\left(x^2-25\right)-\left(x^3-2x^2+4x+2x^2-4x+8\right)=17\)

\(\Rightarrow x^3-25-\left(x^3+8\right)=17\)

\(\Rightarrow x^3-25x-x^3-8=17\)

\(\Rightarrow-25x=25\Rightarrow x=-1\)

Vậy x = -1

Answer 3

x.(x - 5).(x + 5) - (x + 2).(x² - 2x + 4) = 17

<=> -25x - 8 = 17

<=> -17x = 17

<=> x = -1

=> x = -1

Answer 4

Lời giải 

\(\Leftrightarrow-25x-8=17\)

\(\Leftrightarrow-17x=17\)

\(\Leftrightarrow17:\left(-17\right)\)

\(\Leftrightarrow-1\)