Need help on linear equations

• SkillzKills

  25 Mar 09, 20:59

  New questions

  Given that the lines bx = ay + 1 and b - ay - x = 0 intersect at the point (5, -3), what are the values of a and b?

   

   

  A carpenter is paid a normal rate of $x per hour and an overtime rate of $y per hour. If he works for 21 h at the normal rate of pay and 9 h at the overtime rate, he will be paid $69.  However, if he works for 27 h at the normal rate and 3 h at the overtime rate, his earnings will be $63.

  a)       Form two equations in x and y and show that one of the equations reduces to 7x + 3y = 23

  b)       Solve the two simultaneous equations for the value of x and of y.  

• skythewood

  25 Mar 09, 21:04

  15A + 20B = 1025                     ====> got this from the total cash

  A + B = 60                                    ====> got this from the number of shoes.

   

  go solve

• SkillzKills

  25 Mar 09, 21:08

  whats A and what B?

• TownLink 291

  25 Mar 09, 21:09

  Originally posted by skythewood:

  15A + 20B = 1025                     ====> got this from the total cash

  A + B = 60                                    ====> got this from the number of shoes.

   

  go solve

  I help you solve lah..

   

  If A+B = 60,

  15A + 15 B = 900

  1025 - 900 = 125

  20 B - 15 B = 5B

  125 = 5 B

  B = 25.

  Ans: 25 Pairs.

• TownLink 291

  25 Mar 09, 21:09

  Originally posted by SkillzKills:

  whats A and what B?

  A is the number of $15 shoes

  B is the number of $ 20 shoes

• SkillzKills

  25 Mar 09, 21:11

  this is do by linear equation way meh?

• charlize

  25 Mar 09, 21:14

  My maths is also like crap.

   

  But this is simultaneous equations right?

   

  Linear equation?

• SkillzKills

  25 Mar 09, 21:20

  simultaneous linear equation la 

• SkillzKills

  25 Mar 09, 21:23

   

• skythewood

  25 Mar 09, 21:40

  Originally posted by SkillzKills:

  1 more question,

  Given that the lines bx = ay + 1 and b - ay - x = 0 intersect at the point (5, -3), what are the values of a and b?

  for both equation, sub in x= 5, y = -3.

  than you get two equation of a and b.

  go solve.

• SkillzKills

  25 Mar 09, 21:56

  x=5, y=3

  b(5) = a(3) + 1    à 1

  b – a(-3) – 5 = 0  à 2

  From 1,

  B = (a(3)+1)/2        à3

  Sub 3 into 2,

  (A(3)+1)/2 – a(-3) - 5 = 0

  1.5a+0.5 + 3a – 5 = 0

  1.5a+3a+0.5-5 = 0

  4.5a - 4.5 = 0

  Therefore, a = 1

  When a = 1, b = (3+1)/2

                          = 4/2

                          = 2

   

  This isit the ans

• skythewood

  25 Mar 09, 23:57

  Originally posted by SkillzKills:

  <!--StartFragment-->

  x=5, y=3

  b(5) = a(3) + 1    à 1

  b – a(-3) – 5 = 0  à 2

  From 1,

  B = (a(3)+1)/2        Ã 3

  Sub 3 into 2,

  (A(3)+1)/2 – a(-3) - 5 = 0

  1.5a+0.5 + 3a – 5 = 0

  1.5a+3a+0.5-5 = 0

  4.5a - 4.5 = 0

  Therefore, a = 1

  When a = 1, b = (3+1)/2

                          = 4/2

                          = 2

   

  This isit the ans

  <!--EndFragment-->

  
  which part of x = 5, y = -3 you don't understand? -3 means negative 3. redo.