<span>The solution:
= 40, p = q = 0.5
P[x] = nCx *p^x *q^(n-x)
when p = q = 0.5, the formula simplifies to
P[x] = nCx/2^n = 40Cx/2^40
at least 18 of each type means 18 to 22 of (say) type I
P(18 <= X <= 22) = 0.5704095 <-------
qb
mean = 40*0.5 = 20
SD = sqrt(npq) = sqrt(40*0.5*0.5) = 3.1623
z1= (18-20)/3.1623 = -0.63 , z2 = (22-20)/3.1623 = 0.63
P(-0.63 < z < 0.63) = 0.4713 <-------</span>
The number . . . . . N
The difference of the number and 9 . . . N-9
Seven times that difference . . . . . . . 7(N-9)
You said that 7(N-9) = 2 .
Divide each side by 7 : N - 9 = 2/7
Add 9 to each side: N = 9 and 2/7
Answer:
Identity (a) can be re-written as
which we already proven in another question, while for idenity (b)
step A is simply expressing each function in terms of sine and cosine.
step B is adding the terms on the LHS while multiplying the one on RHS.
step C is replacing the term on the numerator with the equivalent from the pithagorean identity 
The amount Rachel has left of the amount given to her by her aunt after she makes the purchases is $22.15.
<h3>How much does Rachel have left?</h3>
In order to determine the amount she would have left, determine the total value of the purchases and subtract it from the amount she was given.
Total value of the purchases = (4 x 0.85) + 45.50 + (5 x 2.79) = $62.85
Change = $85 - $62.85 = $22.15
To learn more about addition, please check: brainly.com/question/19628082
(x-1)(x-1)
=x^2-x-x+1
=x^2-2x+1
(x+7)(x-7)
=x^2-7x+7x-49
=x^2-49
