Hello my friend it is the 21 and 31
Answer:
Step-by-step explanation:
We are to show that 
<u>Proof:</u>
From trigonometry identity;


From trigonometry, 2sinAcosA = Sin2A

Also note that sin(B-C) = sinBcosC - cosBsinC
sin420cos140 - cos420sin140 = sin(420-140)
The resulting equation becomes;

= 
Given:

To find:
The value of x.
Solution:
We have,

To find the value of x, we need to isolate x on one side.
Subtract 2b from both sides.

Divide both sides by -3. On multiplying or dividing an inequality by a negative number, we need to change the sign of inequality.


The required inequality for x is
.
Therefore, the correct option is A.
It increases the mean value of the prizes.
Answer:
Step-by-step explanation:
- -11/2+27/4+(-17/4)
- (-22+27-17)/4
- (-12)/4
- -3