Answer:
1. C
2. D
3. C
Explanation:
1. Girls = 12 plus twice the number of boys, so C. y = 12 + 2x.
2. You have to see which point has the second value being greater than the first value:
A) -1 > -2 is not true
B) 0 > 1 is not true
C) 2 > 3 is not true
D) 8 > 4 is true, so it's D
3. Add the two values and see if it's less than 5
A) -1-4 < 5 is true
B) 0 + 4 < 5 is true
C) 1 + 7 < 5 is not true, so this is the answer
D) 2 + 2 < 5 is true
For these kinds of expressions use FOIL (first, outside, inside, last).
-2x • 9x = -18x^2
-2x • -3y = 6xy
8y • 9x = 72 xy
8y • -3y = -24y^2
Now combine them all:
-18x^2 + 78xy - 24y^2
<span> half life i= 78 hours
amount after 78 hours is 395 kg:
395 = 790e^(k*78)
Dividing by 790 and taking natural log
ln (395/790) = (k*78)
-0.6931 = 78k
-0.00888 = k
lets calculate how much is left after 18 hours:
Amount(18)
= 790e^(-0.00888*18)
Amount = 673.301 kg
hope this helps</span>
376 because 276 + 100 is 376
