Answer:
(D) : Z+7
Step-by-step explanation:
−
1
+
8
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z−1+8
+
7
Hi there!

We are given:
cos(7x)cos(4x) = -1 - sin(7x)sin(4x)
Begin by moving all terms with variables to one side:
cos(7x)cos(4x) + sin(7x)sin(4x) = -1
The corresponding trig identity is cos(A - B). Thus:
cos(7x - 4x) = cos(7x)cos(4x) + sin(7x)sin(4x) = -1
cos(3x) = -1
cos = -1 at π, so:
3x = π
x = π/3
We can also find another solution. Let 3π = -1:
3x = 3π
x = π
Thus, solutions on [0, 2π) are π/3 and π.
For number 3, write something along the lines in your own words like The risks involved in the use of condoms in combating the spread of HIV and AIDS is the condom can break, the condom can be slipped off without knowledge, and the condom does not protect from oral sex.
You are using a^2+b^2=c^2
since c is the hypotenuse
#1 the equation would be 16^2+b^2=34^2
16^2= 256
34^2= 1156
1156-256= 900
b^2=900 (now find square root of 900)
b= 30
You are now trying to find the hypotenuse or c in this so it is simpler
#2 equation - 4^2+2^2=c^2
16+4=c^2
20=c^2
c= 4.27
-6/3 but it can be simplified into -2
Hope this helps