x^2-4|x|+8x=0 equation
The teacher will be very surprised to see your correct solution 😉
The solution
Detail solution
For every modulo expressions in the equation
allow cases, when this expressions ">=0" or "<0",
solve the resulting equation.
1.
$$x \geq 0$$
or
$$0 \leq x \wedge x < \infty$$
we get the equation
$$x^{2} - 4 x + 8 x = 0$$
after simplifying we get
$$x^{2} + 4 x = 0$$
the solution in this interval:
$$x_{1} = -4$$
but x1 not in the inequality interval
$$x_{2} = 0$$
2.
$$x < 0$$
or
$$-\infty < x \wedge x < 0$$
we get the equation
$$x^{2} - 4 \left(- x\right) + 8 x = 0$$
after simplifying we get
$$x^{2} + 12 x = 0$$
the solution in this interval:
$$x_{3} = -12$$
$$x_{4} = 0$$
but x4 not in the inequality interval
The final answer:
$$x_{1} = 0$$
$$x_{2} = -12$$
$$x_{1} = -12$$
$$x_{2} = 0$$
Sum and product of roots
[src]
$$\left(-12 + 0\right) + 0$$
$$-12$$
$$1 \left(-12\right) 0$$
$$0$$