Explanation:
9-x-2x²+4x+6
=15+3x-2x²
=-2x²+3x+15
D=b²-4ac
=3²-4×-2×15
=9+120
=129
x1= (-b+VD)/2a
=(-3+V129)/-4
=(3+V129)/4
x2= (-b-VD)/2a
=(3-V129)/4
4.6m questions
5.9m answers