Answer:
b = 60
Step-by-step explanation:
Using Pythagoras' identity in the right triangle
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
b² + 63² = 87²
b² + 3969 = 7569 ( subtract 3969 from both sides )
b² = 3600 ( take the square root of both sides )
b = 
= 60
I think there is data that is missing. Please attach the drawing so that to help you
39.65 is the approximate value of arccos0.77
the answer is false
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Y=-3x+1
So the answer is A. All you're doing is moving the 3x to the opposite side, and because your switching the side, you need to switch the sign. So it's a negative 3x after you solve for y. Solving for y(or any letter) is just getting that letter alone on one side of the equal sign.
