Algebra

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.04x + 720 - .06x > = 650
-.02x <= -70
x < = -70/-.02
x < = 3500

Or do the sign go the other way like this?


.04x + 720 - .06x > = 650
-.02x > = -70
x > = -70/-.02
x > = 3500

Which would be the solution to solve this inequality?

.04 x + .06(12000-x) >= 650

  • Algebra -

    see my final reply to

    http://www.jiskha.com/display.cgi?id=1247546252

  • Algebra -

    Why is is greater than or = to? I got the answer as being < or = 3500? Can you please explain? Thanks!

  • Algebra -

    Yes, I had agreed that you were right,
    and changed it to ≤

    here is the corrected version

    .04x + 720 - .06x ≥ 650
    -.02x ≥ -70
    x ≥ -70/-.02
    x ≤ 3500

  • Algebra -

    So basically the > = stay the same for the first 2 lines and change to < = for the last? How does that work?

  • Algebra -

    Ok, I will illustrate with an example

    e.g.

    8 > 5 -----> True
    if we add any number or subtract any number the statement is still true

    8+6 > 5+6 ---> True

    let's multiply by a positive number

    8(4) > 5(4) -----> still True !

    how about dividing by a positive

    8/2 > 5/2 ??? Yes, still True

    how about multiplying by a negative

    8(-3) > 5(-3) or
    -24 > -15 BUT THAT IS FALSE !!!
    how do we make it true? We reverse the sign
    -24 < -15 , now it's Truee

    same thing for division by a negative.

    So, in summary,
    you can add/subtract any value just like for equations and the inequality sign stays the same.
    Same is true for multiplying/dividing by a positive number.
    BUT, when you multiply or divide by a negative number in an inequality, you have to reverse the inequality sign at that step. Usually this will be your last step.

  • Algebra -

    Thank you! This is a great review of this topic! Thanks again!

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