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



The answer should be 14.
You just have to substitute x with the given number and finish the equation.
Answer:
Step-by-step explanation:
All votes: 10*3+18+22+15*3+20+8=143
143*0.2(20%)=28.6 about 28vote (Scifi)
Scifi, 10 adults, 18 children, which is 20% of the votes.
Answer:
√105/2
Step-by-step explanation:
Given the surd expression √7.5×√3.5, this can also be expressed as;
√7.5×√3.5
= √75/10 × √35/10
= √(75×35)/10×`10
=√105×25/100
= 5√105/√100
=5√105/10
=√105/2
Hence the required expression a √105/2