1. Answer: D. <span>A = 100 (1/2)^t/13.27
</span>Exponent equation formula would be an= a0( 1+r)^t
In this question, the radio isotopes will become half of its weight after the half-life. So, the ratio would be -0.5 (r= -0.5)
The halftime is 13.27 hours, so the time will be divided by that number. The result would look like this:
an= a0( 1+r)^t
an= a0( 1-0.5)^t/13.27
an= a0( 1/2)^t/13.27
2. Answer: x= 74°
<span>The ladder and the building will make a right triangle with the ladder as the hypotenuse.
The foot of the ladder is 2 feet from the building, so the adjacent side is 2ft.
It reaches a point 7 feet high on the building, so the opposite side is 7ft</span>
You can find the angle by using the tan equation
tan x= opposite / adjacent
tan x= 7/2= 3.5
x= 74°

I believe the above function is what they're looking for.
The answer is true, and let me explain this to you like this:
<span>F(x) = 4x - 6
when x = 1, F(x) = 4 * 1 - 6 = -2
when x = 2, F(x) = 4 * 2 - 6 = 2
when x = 3, F(x) = 4 * 3 - 6 = 6
when x = 4, F(x) = 4 * 4 - 6 = 10
</span><span>second row is: -2, 2, 6, 10
</span><span>differences are: 2 - (-2) = 4; 6 - 2 = 4; 10 - 6 = 4
</span>So, the <span>second row is in arithmetic progression.
Hope this is what you were looking for</span>
Factors of 20: 1, 2, 4, 5, 10, 20
Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36
GCF(20, 36) = 4
Answer: b). 4