Answer: 
Step-by-step explanation:
Three-fifths of the sum of 9 and f is 
=
=
A quadratic equation has the general form
of: <span>
y=ax² + bx + c
It can be converted to the vertex form in order
to determine the vertex of the parabola. It has the standard form of:
y = a(x+h)² - k
This can be done by completing a square. The steps are as follows:
</span><span>y = 3x2 + 9x – 18
</span>y = 3(x2 <span>+ 3x) – 18
</span>y + 27/4= 3(x2 <span>+ 3x+ 9/4) – 18
</span>y = 3(x2 + 3/2)^2 – 99<span>/4
</span>
Therefore, the first step is to group terms with the variable x and factoring out the coefficient of x^2.
Answer:
the answer is 1.7320508076
