Answer:
B. (-7 +/-√33) / 4
Step-by-step explanation:
2x2 + 7x + 2 = 0
x = [-7 +/- √(7^2 - 4*2*2)] / 2*2
x = -7/4 +/- √(33) / 4
= (-7 +/-√33) / 4
The second equation because they all have a common factor of 3. You can get x by itself. However, with the first one, you'll end up with fractions instead.
Answer:

Step-by-step explanation:
Given
← factor both numerator and denominator
=
← cancel common factor (1 - 2b) on numerator/denominator
=
← cancel 6 and 3 by 3
= 
P(at least 5 rolls until 1) = P(4 rolls are not 1) = 5/6 x 5/6 x 5/6 x 5/6 = 0.4823 (4sf)
Fewer than 7 rolls to get second 1 after first takes 3 rolls means second occurs on 4th, 5th or 6th roll
The probability of each of these is 1/6, 5/6 x 1/6 and 5/6 x 5/6 x 1/6 respectively.
P(second 1 on 4th, 5th or 6th roll) = 1/6 + 5/36 + 25/216 = 91/216 = 0.4213 (4sf)