The low temperature during 4 days in september was 21˚c, 21˚c, 19˚c and 19˚
2 answers:
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Between the probability of union and intersection, it's not clear what you're supposed to compute. (I would guess it's the probability of union.) But we do know that
For parts (a) and (b), you're given everything you need to determine
.
For part (c), if
and 
are mutually exclusive, then 
, so 
. If the given probability is 
, then you can find 
. But if this given probability is for the intersection, finding is impossible.
For part (d), if and are independent, then 
.
For parts (a) and (b), you're given everything you need to determine
For part (c), if
For part (d), if
Answer:
see explanation
Step-by-step explanation:
Given
x² - 3x - 40 = 0
Consider the factors of the constant term (- 40) which sum to give the coefficient of the x- term (- 3)
The factors are - 8 and + 5, since
- 8 × 5 = - 40 and - 8 + 5 = - 3, thus
(x - 8)(x + 5) = 0 ← in factored form
Equate each factor to zero and solve for x
x - 8 = 0 ⇒ x = 8
x + 5 = 0 ⇒ x = 5
------------------------------------------------------
Given
4x² - 81 = 0 ← this is a difference of squares and factors in general as
a² - b² = (a + b)(a - b), thus
4x² - 81
=(2x)² - 9²
= (2x + 9)(2x - 9) = 0 ← in factored form
Equate each factor to zero and solve for x
2x + 9 = 0 ⇒ 2x = - 9 ⇒ x = -
2x - 9 = 0 ⇒ 2x = 9 ⇒ x =