What is the vertex of f(x) = x2 + 10x + 16?
A. (2, 6)
B. (1, 5)
C. (5, 9)
D. (-5, -9)

Question

What is the vertex of f(x) = x2 + 10x + 16?
A. 	(2, 6) 
B. 	(1, 5) 
C. 	(5, 9) 
D. 	(-5, -9)

anonymous · Answer

first coordinate of the vertex is always $-\frac{b}{2a}$ which in your case is $-\frac{10}{2}=-5$

anonymous · Answer

the vertex is the highest, or lowest point of a parabola 
it is expressed as -b/2a 
recognize this as part of the quadratic formula? 
the +/-sqrt(b^2-4ac) give the values on either side of the 'Line of Symmetry' 

so -b/2a= -10/2= -5 
this is the x value 

plug -5 into the equation to get the value for y 
(-5)^2+10(-5)+16 
25-50+16 
-9 

the vertex is 
(-5,-9)

anonymous · Answer

is that right ?

anonymous · Answer

second coordinate is what you get when you replace $x$ by $-5$ but since you only have one correct choice you don't even have to do that

anonymous · Answer

yes