Answer:
A and D B and A C and B D and C
Step-by-step explanation:
Answer:

Step-by-step explanation:
We are given that:

Where A and B are positive acute angles.
And we want to find cos(A + B).
Recall that cosine is the ratio of the adjacent side to the hypotenuse. Using this information, find the opposite side with respect to Angle A:

Tangent is the ratio of the opposite side to the adjacent side. Find the hypotenuse with respect to Angle B:

In summary:
With respect to Angle A, the adjacent side is 20, opposite is 21, and the hypotenuse is 29.
With respect to Angle B, the adjacent side is 60, the opposite is 11, and the hypotenuse is 61.
We can rewrite our expression as:

Using the above information, substitute in the appropriate values. Note that since A and B are positive acute angles, all trigonometric values will be positive. Hence:

Simplify:

Answer:

Step-by-step explanation:
The 10 represents the speed traveling downsteam while the 3 represents speed upstream. Downstream you have the help of the current, so it would be x + 2, upstream you are working against the current so it would be x - 2.
10 times 147 equals 1470
10 x 147 = 1470
Number 6 is A because Five times -1 is -5+3×11 equal -2