Announcement

Collapse
No announcement yet.

Prentice Hall Algebra 1, 9.1, #67

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

    Prentice Hall Algebra 1, 9.1, #67

    We need help with the following problem. The sum of the numbers is 13, the product is 36. Find the numbers. The answer is obvious, and we can write the individual equations, but we cannot figure out what process to use (elimination, etc) to work out the problem. Thank you for your help.
    Tina R
    DS-14 (9th grade) -9M, MPOA Intro to Physics

    #2
    Write two equations:
    x + y = 13
    x*y = 36
    Solve the first equation for x: x = 13 - y
    Substitute into the second equation: (13-y)*y = 36
    Simplify the new quadratic equation, and set equal to zero: y^2 - 13y +36 = 0
    Factor the quadratic: (y - 9)(y - 4) = 0
    two values of y make this true: y=9 or y=4
    Subst y = 9 into original 1st equation and solve for x (4,9)
    Subst y = 4 into original equation and solve for x (9,4)

    The two numbers that satisfy the problem are 4 and 9 (which you knew!)
    We do these "simple" problems to master the methods, so that we can later solve problems that don't have obvious answers. (Just in case your son asks!)
    Cindy Davis
    Science and Math teacher at Highlands Latin School - Indianapolis
    ds-24 college graduate: working, reading, writing
    ds-23 college graduate: 1st year med school
    dd-21 college junior: Nursing

    Comment


      #3
      Thank you, Cindy! I found the solutions manual from another thread on here. Does anyone have a link for the algebra II solution manual? I looked on Amazon, but I'm not sure it is for the correct text.
      Tina R
      DS-14 (9th grade) -9M, MPOA Intro to Physics

      Comment


        #4
        Originally posted by trob View Post
        Thank you, Cindy! I found the solutions manual from another thread on here. Does anyone have a link for the algebra II solution manual? I looked on Amazon, but I'm not sure it is for the correct text.
        This thread has more information on the Algebra II solutions manual. In particular, posts 11-12 explain the different PH Classics editions and include a link to Prentice Hall's webpage for the version MP uses.

        HTH!
        Michael
        Memoria Press

        Comment

        Working...
        X