In the general form of the equation y = mx + c, the slope is given by m.
The equation from the question can be rearranged a little to give y = -x -5, thus we can now compare directly with the general form above and see that m = -1, and so the answer is B.
The answer is D because if you use the formula perfectly
Answer:
480
Step-by-step explanation:
Sn = n÷2 × (2a + (n-1)d)
n = 20 a = -14 d = 4
S20 = 10 × (-28 + 19 × 4) = 480
Answer: 6 : 24 is for black haired and 18 : 24 is for blond
Step-by-step explanation:
18 : 24
24 - 18 = # of black haired dolls
6 = # of black haired dolls
Ratio
6 : 24
Answer:
18 minutes
Step-by-step explanation:
A = A₀ (½)^(t / T)
where A is the final amount,
A₀ is the initial amount,
t is the time,
and T is the half life.
A = 140 when t = 10. Solve for the half life:
140 = 700 (½)^(10 / T)
0.2 = ½^(10 / T)
log 0.2 = (10 / T) log 0.5
10 / T = 2.32
T = 4.31
When A = 40, t is:
40 = 700 (½)^(t / 4.31)
0.057 = ½^(t / 4.31)
log 0.057 = (t / 4.31) log 0.5
t / 4.31 = 4.13
t = 17.8
Rounded to the nearest whole number, it takes 18 minutes.
