Answer:
The vertex of this parabola, 
, can be found by completing the square.
Step-by-step explanation:
The goal is to express this parabola in its vertex form:
,
where 
, 
, and 
are constants. Once these three constants were found, it can be concluded that the vertex of this parabola is at 
.
The vertex form can be expanded to obtain:
.
Compare that expression with the given equation of this parabola. The constant term, the coefficient for 
, and the coefficient for 
should all match accordingly. That is:
.
The first equation implies that is equal to 
. Hence, replace the "
" in the second equation with 
to eliminate 
:
.
.
Similarly, replace the "" and the "" in the third equation with and 
, respectively:
.
.
Therefore, 
would be equivalent to 
. The vertex of this parabola would thus be:
.
See https://web2.0calc.com/questions/need-help-now_10.
Answer:
20 questions.
Step-by-step explanation:
Let x be the number of questions on the quiz.
85
% means 85 out of 100 (or 85/
100 )
85/
100
= 3/x
--->100-85=15
--->15/3=5
--->100/5=20
Meaning each question was worth 5% and there were 20 questions.
