Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Trending News

Promoted
?
? asked in Science & MathematicsMathematics · 3 years ago

SAT Practice Math problem. PLEASE HEP (desperate ---> me)?

Constants in math always confuse me and I'm trying to learn how to solve for problems like this:

(X-8)(x-k)=x^2 - 5kx + m

In the equation above, k and m are constants. If the equation is true for all values of x, what is the value of m?

I've tried looking up videos on YouTube and Khan Academy with zero luck. if you can find or film a video for me solving problems like this, that would be amazing. Thanks!

2 Answers

Relevance
  • Steve A
    Lv 7
    3 years ago

    -8 + (-k) = -5k

    2 = k

    -8k = m

    m = -16

  • Some Body
    Lv 7
    3 years ago

    This is just a matter of distributing and matching the coefficients/constants.

    (x-8)(x-k)=x² - 5kx + m

    Use FOIL method to distribute (first, outer, inner, last):

    x² - kx - 8x + 8k = x² - 5kx + m

    Combine like terms:

    x² - (k + 8)x + 8k = x² - 5kx + m

    Matching the coefficient:

    k + 8 = 5k

    8 = 4k

    k = 2

    Matching the constant:

    8k = m

    8(2) = m

    16 = m

Still have questions? Get your answers by asking now.