If the parabola has y = -4 at both x = 2 and x = 3, then since a parabola is symmetric, its axis of symmetry must be between x = 2 and x = 3, or at x = 5/2. Our general equation can then be:
y = a(x - 5/2)^2 + k
Substitute (1, -2): -2 = a(-3/2)^2 + k
-2 = 9a/4 + k
Substitute (2, -4): -4 = a(-1/2)^2 + k
-4 = a/4 + k
Subtracting: 2 = 2a, so a = 1. Substituting back gives k = -17/4.
So the equation is y = (x - 5/2)^2 - 17/4
Expanding: y = x^2 - 5x + 25/4 - 17/4
y = x^2 - 5x + 2 (This is the standard form.)
Answer:
4) 0.001
Step-by-step explanation:
The amount (a) present in h hours is ...
a(h) = (initial value)×(1/2)^(h/(half-life))
6 days is 6×24 hours, so the amount remaining is ...
a(6×24) = 50×(1/2)^(6×24/9) = 50/2^16 ≈ 0.001 . . . . milligrams
Answer:
43
Step-by-step explanation:
3 4
—- = —-
x 5
cross multiply 3 and 5 = 15
and 4 and x = 4x
you get 15=4x
x= 15/4
