Solve the problem.Let (a, b) and (c, d) be two points in the first quadrant, and let ? be the angle between the line segment connecting (a, b) with the origin and the line segment connecting (c, d) with the origin. It can be shown that cos ? = .Find ? if    and 

style="vertical-align: -4.0px;" /> Give your answer in degrees rounded to the nearest hundredth.

A. 75.35°
B. 108.43°
C. 55.30°
D. 34.70°

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Answer: D

Mathematics

Which of the following is a definition of a dilation? ?

A. ?The shape maintains its proportionality but shrinks/grows in size. B. ?The shape undergoes a rigid transformation. C. ?The shape translates horizontally or vertically, and flips. D. ?The shape changes its proportionality as it moves vertically, horizontally, or diagonally. E. ?The shape rotates 90?, maintaining a rigid transformation.

Write a matrix equation equivalent to the system of equations.3x - 9y + 12z = 4-4x + 3y - 10z = 3

A.
 = 
B.
  = 
C.
  = 
D.
  = 

Use a graphing utility to graph the function over the indicated interval and approximate any local maxima and local minima. If necessary, round answers to two decimal places.f(x) = x3 - 12x + 2; (-5, 5)

A. local maximum at (-2, 18) local minimum at (0, 0) local minimum at (2, -14) B. local maximum at (-2, 18) local minimum at (2, -14) C. local minimum at (0, 0) D. none

Multiply the polynomials and simplify by combining like terms.(x2 + x - 2)(x2 + x - 7) 

A. x4 + x3 + 10x2 + 9x + 14 B. x4 + 2x3 + 9x2 + 5x + 14 C. x4 + 2x3 - 8x2 - 9x + 14 D. x4 + x3 - 9x2 - 9x + 14