Answer:
I think it is D I am going to guess on that
Answer:
<u><em>note:</em></u>
<u><em>solution is attached</em></u>
Well first off if you have a negative sign in front of the seven, DO NOT have a plus sign because it will be confusing. So y-7=13? , You add 7 to 13 and = 20, so y= 20
Answer:

Step-by-step explanation:
<u>Use identities to set the equation up as a quadratic</u>

<u>Make the substitution u=cos(x) and solve the quadratic</u>
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Hence, 
–6x + 2y = 3/2
or, 2y= 6x + 3/2
or, y= (6x + 3/2)/2
or, y = 6x/2 + 3/4
or, y = 3x + 3/4
Therefore, –6x + 2y = 3/2 is Sandra's equation.