Answer:
Just took the test, its B
Step-by-step explanation:
Answer:
y=x7 X 5
Step-by-step explanation:
Once the cake is removed from the oven, it has been exposed to the room temperature of 70°F. After 10 minutes, the cake's temperature decreased to 200°F, which is 150°F cooler than it initially was (350°F). As for the what is asked, 90°F is 260°F cooler than its original temperature (350°F).
This problem can be expressed in a ratio:
10mins:150<span>°F = N:260</span><span>°F
where N is how long it will take for</span><span> cake to cool to 90°F
</span>150<span>°FxN=10x260
</span>150N=2600
N=2600/150
N=17.33
N<span>≈20 minutes
Thus, it takes approximately 20 minutes </span><span>for the cake to cool to 90°F</span>
Answer:
C 2
Step-by-step explanation:
This is a parabolic function
Notice how we go negative and then positive
y = ax^2 +bx+c
Let x = 0
-5 = a(0) + b(0) +c
c = -5
y = ax^2 + bx -5
Let x = 3
4 = a(3)^2 +b(3) -5
Let x=-3
4 = a(3)^2 -b(3) -5
Add the two equations
4 = a(3)^2 +b(3) -5
4 = a(3)^2 -b(3) -5
----------------------------
8 = 2a (3)^2 - 10
18 = 2 a(9)
18 = 18a
a =1
Solving for b
4 = 1(3)^2 -b(3) -5
4 = 9 -3b -5
4 = 4 -3b
0 = -3b
0 =b
The equation is
y = (x)^2 -5
Letting y = -1
-1 =x^2 -5
Adding 5 to each side
4 = x^2
Taking the square root of each side
±2 = x
x= ±2
Given the choices
