Without drawing the graph of the equation, determine how many points the parabola has in common with the x-axis and whether its vertex lies above, on, or below the x-axis.

y = –2x2 + x + 3

Question

Without drawing the graph of the equation, determine how many points the parabola has in common with the x-axis and whether its vertex lies above, on, or below the x-axis.
 
    y = –2x2 + x + 3

anonymous · Answer

set y=0? the find derivative of y

anonymous · Answer

common with x-axis, x=3/2, x=-1.........dy/dx=-4x+1=0, solve for x=1/4, plug 1/4 back to equation y, and if y is positive, above/ negative below, 0 on

anonymous · Answer

A.
1 point in common; vertex on x-axis
 
 B.
2 points in common; vertex below x-axis
 
 C.
2 points in common; vertex above x-axis
 
 D.
no points in common; vertex below x-axis

anonymous · Answer

C