I would not know the answer to this question sorry
105 divided by 6 equals 17. 5
She should buy 18 packages
To find the amount of miles/gallon, we have 540 miles/18 gallons=30 miles/gallon. As we add 30 miles for every gallon, the amount of miles traveled is 30*x (e.g. if x is 1 then 0+30=30 and if x is 2 then 30+30 (2 times)=60) with x being the amount of gallons. For b, we just plug 12 in for x to get 20*12=360
I assume you're supposed to establish the identity,
cos(A) cos(2A) cos(4A) = 1/8 sin(8A) / sin(A)
Recall the double angle identity for sine:
sin(2<em>x</em>) = 2 sin(<em>x</em>) cos(<em>x</em>)
Then you have
sin(8A) = 2 sin(4A) cos(4A)
sin(8A) = 4 sin(2A) cos(2A) cos(4A)
sin(8A) = 8 sin(A) cos(A) cos(2A) cos(4A)
==> sin(8A)/(8 sin(A)) = cos(A) cos(2A) cos(4A)
as required.
