The length of side A in centimeters is 6cm
D. 6
First solve for theta in 'x' equation:

Substitute into 'y' equation:

Simplify by rewriting cos in terms of sine.
Using pythagorean identity:


Simplify using inverse function property:

Answer:
-3x(2y^5+5x^3-3)
Step-by-step explanation:
-6xy^5 - 15x^4 + 9x
-6xy^5-15xx^3+9x
2*3xy^5+5+3xx^3z+3*3x
Factor:
-3x(2y^5+5x^3-3)
It is: you use distribution method to solve the problem.
14m + 42 + 56m
Then you combine like terms:
14m + 56m + 42
Then you add
70m + 42 is your answer