+386 I have f(x)=5x^2 - 7x
x of summit "S":
x= -b/2a
x= - (-7) / 2(5)
x= 7/10
y of summit "S":
y= 5 (7/10)^2 - 7 (7/10)
y= 49/20 - 49/70
y=49/20 - 14/20 = 35/20 = 7/5
Coords of summit "S": (7/10, 7/5)
Do I make sense?
+33661 You make sense until this line: y= 49/20 - 49/70
This doesn't follow from: y= 5 (7/10)^2 - 7 (7/10)
You should have: y = 49/20 - 49/10 instead
I'll leave you to take it from there.
And it isn't a peak, it's a trough:
.
+386 I don't speak english so fluently, so I used peak regardless of the direction the opening faces, sorry.
Could you explain to me why 7 (7/10) would = 49/10?
