Find the center and the radius of the circle.x2 + y2 - 8x + 4y + 20 = 81
A. (-2, 4); r = 9
B. (2, -4); r = 81
C. (-4, 2); r = 81
D. (4, -2); r = 9
Answer: D
Mathematics
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Determine the principal value without using a calculator.
A. 
B. 3
C. 2
D. 
Mathematics
Write the trigonometric expression as an algebraic expression containing u and v.cos(sin-1 u + cos-1 v)
A. uv - (
)(
)
B. v
+ u
C. v
- u
D. uv + (
)(
)
Mathematics
Find the direction the parabola opens, the coordinates of the vertex, the equation of the axis of symmetry and draw the graph.x = -(y + 1)2 + 6
A. 
opens left; vertex (1, -6);
axis of symmetry y = -6
B. 
opens left; vertex (6, -1);
axis of symmetry y = -1
C. 
opens left; vertex (-1, 6);
axis of symmetry y = 6
D. 
opens left; vertex (6, 1);
axis of symmetry y = 1
Mathematics
Evaluate the expression.
+ 
A. 
B. 
C. 
D. 
Mathematics