Answer is <span>C. 9x-2y=-40
hope that helps
because y = 9/2x +20 then 2y = 9x + 40 so 9x -2y = -40
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25% of 8 is 2, 8-2=6
2 are red, 6 are blue
We'll use the following properties of sine and cosine to prove this:



Then it's just a matter of filling it in...
sin20sin40 * sin60sin80 = 1/2(cos20 - cos60) * 1/2 (cos20 - cos140) =
1/8( cos40 + 1 - cos160 - cos120 - cos40 - cos80 + cos80 + cos200) =
1/8(1 - cos160 - cos120 + cos200) =
1/8(1 - cos160 - cos120 + cos160) =
1/8(1 - cos120 ) = 1/8( 1 + 1/2 ) = 3/16
The answer is x=7 and y=3