y = 1 + x y = 3 + x 3 {\displaystyle {\begin{aligned}&\color {red}\mathbf {y=1+{\sqrt {x}}} &\color {royalblue}\mathbf {y={\frac {3+x}{3}}} \\\\\end{aligned}}}
1 + x = 3 + x 3 1 + x − 3 + x 3 = 0 3 + 3 x 3 − 3 + x 3 = 0 3 + 3 x − 3 + x = 0 3 x + x = 0 3 x = − x 9 x = x 2 9 x − x 2 = 0 x ( 9 − x ) = 0 x = 0 , 9 {\displaystyle {\begin{aligned}1+{\sqrt {x}}&={\frac {3+x}{3}}\\1+{\sqrt {x}}-{\frac {3+x}{3}}&=0\\{\frac {3+3{\sqrt {x}}}{3}}-{\frac {3+x}{3}}&=0\\3+3{\sqrt {x}}-3+x&=0\\3{\sqrt {x}}+x&=0\\3{\sqrt {x}}&=-x\\9x&=x^{2}\\9x-x^{2}&=0\\x(9-x)&=0\\x&=0,9\end{aligned}}}
