1. Reduce <span>3x2-6x-240 to x^2 - 2x - 80

2. Use " ^ " to indicate exponentiation

3. Factor </span>x^2 - 2x - 80 using completing the square:

x^2 - 2x + 1^2 - 1^2 - 80

(x+1)^2 - 1 - 80
(x+1)^2 - 81
(x+1)^2 - 9^2 = (x+1-9)(x+1 +9), or (x-8)(x+10)

Final answer, with all factors shown: 3(x-8)(x+10)

4 0

3 years ago

A set of average city temperatures in May are normally distributed with a mean of 20.66 ^\circ \text{C}20.66

Angelina_Jolie [31]

Answer:

0.9962

Step-by-step explanation:

The z score shows the number of standard deviations by which the raw score is above or below the mean. If the raw score is above the mean then the z score is positive but if the raw score is less than the mean then the raw score is negative. The z score is given by:

$z=\frac{x-\mu}{\sigma}\\ \\\mu=mean,\sigma=standard\ deviation, x=raw\ score$

μ = 20.66°C, σ = 2°C

For x < Singapore temperature, i.e. x < 26

$z=\frac{x-\mu}{\sigma} =\frac{26-20.66}{2}=2.67$

From the normal distribution table P(x < 26) = P(z < 2.67) = 0.9962

4 0

3 years ago