Answer:

Step-by-step explanation:
we know that

Remember the identity

step 1
Find the value of 
we have that
The angle alpha lie on the III Quadrant
so
The values of sine and cosine are negative

Find the value of sine

substitute




step 2
Find the value of 
we have that
The angle beta lie on the IV Quadrant
so
The value of the cosine is positive and the value of the sine is negative

Find the value of cosine

substitute




step 3
Find cos (α + β)

we have




substitute



Answer:
The answer is B
Step-by-step explanation:
862,840 is rounded to 900,000
Answer:
15
Step-by-step explanation:
3 and 5 are not common denominators so you have to find the lowest common denominator which is 15 because 3 times 5 is 15
Betty : Adam
6 : 24
1 : 4
The answer is 1 : 4
Hope this helps.