math questions help!!!!!!!!!!!!!!!!!!!!!!!

Question

21.
Find the slope of the line that passes through the points (6, -4) and (2, -4).

22.
The slopes of two lines are both 5. Because of this, we can conclude that these two lines are which of the following?

A.Parallel

B.Perpendicular

C.Horizontal

D.None of these




23.
Line C passes through the points (-3, -6) and (-1, -12). What is the slope of the line perpendicular to Line C?

24.
Select the equation of the line parallel to the equation y = -3x - 5 that passes through the point (1, 2).

A.y = -3x + 5

B.y = -3x + 6

C.y = -3x - 3

D.y = 3x - 1

Answer 1

21) Given points are (6, -4) and (2, -4)

     Slope of the line m = (y2-y1)/(x2-x1)

                                        = (-4+4)/(2+4)

                                        = 0/6 = 0

 

Comments

denominator substitution was wrong;i think denominator is (2-6=-4)

Answer 2

22) If the slopes of two lines are both 5 i.e, m1 = m2 = 5, we can conclude that these two lines are parallel.

 

Answer 3

23) Given that the line C passes through the points (-3, -6) and (-1, -12)

      Therefore slope of the line C, m1 = (y2-y1)/(x2-x1)

                                                      = (-12+6)/(-1+3)

                                                      = -6/2

                                                      = -3

     If two lines are perpendicular then the product of their slopes equal to -1

                 then   m1*m2 = -1

                     => -3*m2 = -1

                     => m2 = -1/-3

                                = 1/3.

       Therefore the slope of the line perpendicular to line C is 1/3.

Answer 4

24) Let the equation of the line parallel to the equation y = -3x - 5 be y = -3x + k

     Now to find k value substitute the point(1,2) in the above equation, we get

                                                            2 = -3*1 + k

                                                                                2 = -3 +k

                                                                                k = 5

       Therefore after substituting k value we get the equation of the line parallel to the given line.

        That is  y = -3x + 5.