1) A. Biased because the population could be uneven. Too many of one ethnicity, too many of one gender, etc.
2) I believe this one is C. because there are not enough people. You need to survey the majority of parents instead of a selected few.
3) There are 80 green marbles per 500, therefore calculate the percentage.

or

percent. Multiply

percent or

times 25. It gives you

.
4) This one is a probability thing too. For every 500 batteries, there are 3 that are defective, therefore,

.

5) Yet another one. Add up all the nuts and you get

. The chance of getting a cashew from these

is:

.
Therefore:
−3x + 4 - (<span>5x−2)
= </span>−3x + 4 - 5x + 2
= - 8x +6
answer is <span>−8x+6 (first choice)</span>
Answer:

Step-by-step explanation:
Half the length of the palindrome can be any possible sequence of the 26 available letters. The other half is constrained to be the reverse of the same sequence. For odd length sequences, the middle letter can be any of the 26.
So, for k even, the number of palindromes is 26^(k/2). For k odd, the number is 26·26^((k-1)/2) = 26^)((k+1)/2).
Yearly salary would be 240,000 for 5,000 and 48,000 for 1,000 a week
Answer:
x ≈ 1.32, x ≈ - 5.32
Step-by-step explanation:
Given
x² + 4x - 7 = 0 ( add 7 to both sides )
x² + 4x = 7
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(2)x + 4 = 7 + 4
(x + 2)² = 11 ( take the square root of both sides )
x + 2 = ±
( subtract 2 from both sides )
x = - 2 ± 
Thus
x = - 2 -
≈ - 5.32 ( to 2 dec. places )
x = - 2 +
≈ 1.32 ( to 2 dec. places )