The teacher will be very surprised to see your correct solution 😉
The solution set is obviously symmetric with respect to the $y$-axis. Therefore we may assume $x\geq 0$. In the domain $\{(x,y)\in {\mathbb R}^2\ |\ x\geq0\}$ the equation is equivalent with\n$$x^2+ y^2 -1=x^{2/3} y\ ,$$\nwhich can easily be solved for $y$:\n$$y={1\over2}\bigl(x^{2/3}\pm\sqrt{x^{4/3}+4(1-x^2)}\bigr)\ .$$\nNow plot this, taking both branches of the square root into account. You might have to numerically solve the equation $x^{4/3}+4(1-x^2)=0$ in order to get the exact $x$-interval.
Move free summands (without y3) from left part to right part, we given: $$- x_{2} y_{3} + 3 x_{2} + 3 y_{2} = 3$$ Move the summands with the other variables from left part to right part, we given: $$- x_{2} y_{3} + 3 y_{2} = - 3 x_{2} + 3$$ Divide both parts of the equation by (3*y2 - x2*y3)/y3
y3 = 3 - 3*x2 / ((3*y2 - x2*y3)/y3)
We get the answer: y3 = 3*(-1 + x2 + y2)/x2
The solution of the parametric equation
Given the equation with a parameter: $$- x_{2} y_{3} + 3 x_{2} + 3 y_{2} - 3 = 0$$ The coefficient at y3 is equal to $$- x_{2}$$ then possible cases for x2 : $$x_{2} < 0$$ $$x_{2} = 0$$ Consider all cases in more detail: With $$x_{2} < 0$$ the equation $$3 y_{2} + y_{3} - 6 = 0$$ its solution $$y_{3} = - 3 y_{2} + 6$$ With $$x_{2} = 0$$ the equation $$3 y_{2} - 3 = 0$$ its solution