Answer:
119.2
Step-by-step explanation:
Given the following :
Mean (m) = 100 years
Standard deviation (sd) = 15 years
closest to the age of a Galápagos Islands giant tortoise at the 90th percentile of the
distribution?
Obtain the Zscore for 90th percentile (0.90) on the z table = 1.28
Zscore = (X - mean) / standard deviation
1.28 = (X - 100) / 15
1.28 × 15 = X - 100
19.2 = X - 100
19.2 + 100 = X
X = 119.2
Answer:9a^2+18a-72
Step-by-step explanation:
9(a+1)^2-81
9(a+1)(a+1)-81
Open brackets
9(a^2+a+a+1)-81
9(a^2+2a+1)-81
9a^2+18a+9-81
9a^2+18a-72
Answer: 
<u>Cross-multiply</u>
<u></u>
<u></u>
<u></u>
<u></u>
<u></u>
<u></u>
<u></u>
<u>Flip the equation</u>
<u></u>
<u></u>
<u></u>
<u>Divide both sides by 3</u>
<u></u>
<u></u>
<u></u>
<u></u>
