Answer:
d. c = 100; (x – 10)²
Step-by-step explanation:
Note that (x+a)²=x²+2ax+a².
In our case, 2a=-20, so 'a' must be -10.
Since c=a², and a=-10, c=(-10²)=100.
Since a=-10, the perfect square is (x – 10)²
Answer:

Step-by-step explanation:
f=v+at
It requires you to make a the subject of the formula
f-v=at
Dividing both sides by t then

Therefore, the equivalent for a is 
Answer:
1.76
Step-by-step explanation:
Answer:
Mean age: 48
Standard deviation: 4
Step-by-step explanation:
a) Mean
The formula for Mean = Sum of terms/ Number of terms
Number of terms
= 42 + 54 + 50 + 54 + 50 + 42 + 46 + 46 + 48+ 48/ 10
= 480/10
= 48
The mean age is 48
b) Standard deviation
The formula for Standard deviation =
√(x - Mean)²/n
Where n = number of terms
Standard deviation =
√[(42 - 48)² + (54 - 48)² + (50 - 48)² +(54 - 48)² + (50 - 48)² +(42 - 48)² + (46 - 48)² + (46 - 48)² + (48 - 48)² + (48 - 48)² / 10]
= √-6² + 6² + 2² + 6² + 2² + -6² + -2² + -2² + 0² + 0²/10
=√36 + 36 + 4 + 36 + 4 + 36 + 4 + 4 + 0 + 0/ 10
=√160/10
= √16
= 4
The standard deviation of the ages is 4
4 - 2(x + 3) = 5
4 - 2x - 6 = 5
-2x - 2 = 5
-2x = 5 + 2
-2x = 7
x = -7/2 or = -3 1/2