Step-by-step explanation:
To find a, the leading coeffiecent of the quadratic is a.
So a is 2.
To find b, we must use the formula
[tex] - \frac{b}{2a} [/tex]
[tex] \frac{ - ( - 3)}{2(2)} = \frac{3}{4} [/tex]
So b=3/4.
To find c, plug in 3/4 into the function,
which we get
[tex]2( \frac{9}{16} ) - 3( \frac{3}{4} ) + 21[/tex]
[tex] \frac{9}{8} - \frac{9}{4} + 21 = \frac{9}{8} - \frac{18}{8} + 21 = - \frac{9}{8} + 21 = 19.875[/tex]
So c=19.875
