Tam giác $HAB$ là tam giác:

$\left( {2 + x} \right).{x^2}$

$2 + {x^2}$

$67{x^2}$

$2y + 1$

$x = \dfrac{{ - 1}}{2}$

$x = \dfrac{1}{2}$

$x =  - 2$

$x = 2$

$f\left( x \right) - g\left( x \right) + h\left( x \right) = 2x$

$f\left( x \right) - g\left( x \right) + h\left( x \right) = 2x + 1$

$f\left( x \right) - g\left( x \right) + h\left( x \right) = 2x + 3$

$f\left( x \right) - g\left( x \right) + h\left( x \right) = 4{x^2} + 2x + 1$

$f\left( x \right) - g\left( x \right) + h\left( x \right) = 2x$

$f\left( x \right) - g\left( x \right) + h\left( x \right) = 2x + 1$

$f\left( x \right) - g\left( x \right) + h\left( x \right) = 2x + 3$

$f\left( x \right) - g\left( x \right) + h\left( x \right) = 4{x^2} + 2x + 1$

$OA = 2OD$

$OA = 3OD$

$3OA = 2OD$

$2OA = 3OD$

$OA = OB$

$OC$ là phân giác góc $xOy$

$BC \,\bot \,{\rm{Ox}}$

Cả A, B, C đều đúng