Đáp án:
\(\left[ \begin{array}{l}x=\dfrac{\sqrt{17}+9}{2}\\x=\dfrac{-\sqrt{17}+9}{2}\end{array} \right.\)
Giải thích các bước giải:
`x^2-9x+16=0`
`-> x^2-2.x. 9/2+(9/2)^2-(9/2)^2+16=0`
`-> (x-9/2)^2-17/4=0`
`-> (x-9/2)^2=17/4`
`-> (x-9/2)^2-(sqrt(17)/2)^2=0`
`-> (x-9/2-sqrt(17)/2)(x-9/2+sqrt(17)/2)=0`
`-> (x-(9+sqrt(17))/2)(x+(-9+sqrt(17))/2)=0`
`->` \(\left[ \begin{array}{l}x=\dfrac{\sqrt{17}+9}{2}\\x=\dfrac{-\sqrt{17}+9}{2}\end{array} \right.\)
