Question

 

Tìm x

\(\frac{x-18}{x+4}=\frac{x-17}{x+16}\)

Answer 1

Dễ lắm bạn ạ 

\(\frac{x-18}{x+4}=\frac{x-17}{x+16}\)

\(\Leftrightarrow\left(x-18\right)\left(x+16\right)=\left(x+4\right)\left(x-17\right)\)

\(\Leftrightarrow x^2+16x-18x-288=x^2+4x-17x-68\)

\(\Leftrightarrow x^2-2x-288=x^2-13x-68\)

\(\Leftrightarrow x^2-x^2-2x+13x=-68+288\)

\(\Leftrightarrow11x=220\)

\(\Leftrightarrow x=20\)

Answer 2

(x-18)(x+16)=(x+4)(x-17)

x²-2x--288=x²-13x-68

x²-x²-2x+13x-288+68=0

11x=220

x=220:11

x=20