y=(2x+3)2=4x2+12x+9=4(x2+3x+9/4)=4(x+3/2)2, which is vertex form, with vertex at (-3/2,0).
y=(3-x)(2x+5)=6x+15-2x2-5x=-2x2+x+15,
y=-2(x2-x/2-15/2)=-2(x2-x/2+1/16-1/16-15/2),
y=-2(x-¼)2+1/8+15=-2(x-¼)2+121/8.
PROPERTIES
y-121/8=-2(x-¼)2 is in vertex form so vertex is (¼,121/8). The lead coefficient -2 is negative, showing this parabola to be an inverted U shape so the vertex is the maximum. The axis of symmetry is x=¼. The x-intercepts are 3 and -5/2 (from the given factors) and the y-intercept is 15.