General vertex form:

Given :

Extract "spread factor" m

Complete the square


Write as a squared binomial and simplify the constant

Re-write to match signs of standard general form:

Answer:
13.6
Step-by-step explanation:
5 divided into 68 is basically the same thing as 68 divided by 5.
68/5 is equal to 13.6
Plug in 4 for x and solve equation like so. c=2
2 42/100 turn it to a fraction