Answer:
140 minutes
Step-by-step explanation:
After 28 mins you've gone 4 miles, assuming this rate is constant and you dont slow down or speed up, in order to get to 20 miles you will have run 5x as much (20/4 = 5), thus 5x the amount of time (28x5).
20/4 = 5
5x28 = 140
Answer:
The vertex of this parabola, , can be found by completing the square.
Step-by-step explanation:
The goal is to express this parabola in its vertex form:
,
where , , and are constants. Once these three constants were found, it can be concluded that the vertex of this parabola is at .
The vertex form can be expanded to obtain:
.
Compare that expression with the given equation of this parabola. The constant term, the coefficient for , and the coefficient for should all match accordingly. That is:
.
The first equation implies that is equal to . Hence, replace the "" in the second equation with to eliminate :
.
.
Similarly, replace the "" and the "" in the third equation with and , respectively:
.
.
Therefore, would be equivalent to . The vertex of this parabola would thus be:
.
248 divided by 4 equals 62 miles per hour.
0.25 or 1/4 as a fraction
Plug in (4,64) into each answer choice.
A) 4(2)^x
64 =4(2)^4
64 = 4(16)
64 = 64
Answer choice A is correct.
B) f(x) = 2(4)^x
64 = 2(4)^4
64 = 2(256)
64 ≠ 512
Answer choice B is incorrect.
C) f(x) = 4(2)^{-x}
64 = 4(2)^{-4}
64 = 4(-0.0625)
64 ≠ 0.25
Answer choice C is incorrect.
D) f(x) = 2(4)^{-x}
64 = 2(4)^{-4}
64 = 2(0.00390625)
64 ≠ 0.0078125
Answer choice D is incorrect.
Your answer is B<span>) f(x)=2(4)^x</span>