First question:
4(3x-5) + (2x -2)(4 + 3x-5)
Simplify -----> 12x - 20 + (2x-2)(3x-1)
Multiply the second part -----> 12x - 20 + 6x^2 -8x + 2
Combine like terms --------> 6x^2 + 4x - 18
Each side of the addition sign represents one of the rectangles above which is then added to get the area of the entire figure.
Second question:
The average is the summation of each data value divided by the number of data values. So it would be
(4 + 5 + 9)/ 3
Simplify ------> 18/3
Divide --------> 6
Answer: 0.16
Step-by-step explanation:
Given that the run times provided are normally distributed ;
Mean(x) of distribution = 3 hours 50 minutes
Standard deviation(s) = 30 minutes
The probability that a randomly selected runner has a time less than or equal to 3 hours 20 minutes
3 hours 20 minutes = (3 hrs 50 mins - 30 mins):
This is equivalent to :
[mean(x) - 1 standard deviation]
z 1 standard deviation within the mean = 0.84
z, 1 standard deviation outside the mean equals:
P(1 - z value , 1standard deviation within the mean)
1 - 0.8413 = 0.1587
= 0.16
Answer: 
Step-by-step explanation:
To solve for b, we want to use the Pythagorean Theorem as given.
b and 7 are the legs, and 12 is the hypotenuse.
[exponent]
[subtract both sides by 49]
[square root both sides]

Now we know
.
Answer:
45
Step-by-step explanation:
KL = 12 because the triangle is isosceles ( base angles are congruent)
KJ = JM = 12 because the triangle is equilateral ( all angles are equal 60°)
the perimeter is
P = 9 + 12 + 12 +12 = 9 +36 = 45
Answer:
36
Step-by-step explanation:
18=a/2
2*18=a
36=a