Question

F(x)=x2-8x+2
vertex? Again, I used -b/2a but it wasn't right ! What am I doing wrong??

Answer 1

ok in this case a = 1 and b = -8 so
\[-\frac{b}{2a}=-\frac{-8}{2}=4\]

Answer 2

plug in 4 for x get
\[4^2-8\times 4 + 2=16-32+2=-16+2=-14\]

Answer 3

vertex is (4,-14)

Answer 4

now sure what you did wrong but my guess is that you may have put \[-\frac{b}{2a}=-4\] but there are two minus signs (one in the formula and one from the -8)

Answer 5

Thank you again! My teacher is horrible at this, se explains nothing!

Answer 6

hope this helps