Please solve 7d^2-21d?

please show your work

2 Answers

  • Anonymous
    9 years ago
    Favorite Answer

    We have 7d^2 - 21d to solve. Here's the solution:

    Given: 7d^2 - 21d

    We take out d has the common factor. This gives us:

    7d (d - 3) (this is a half equation)

    We need to make 7d (d - 3) into a FULL equation. To do this, we'll equate 7d (d-3) to 0. This gives us:

    7d (d - 3) = 0

    Now we have to ask ourself "what value of d will make the left hand side of the equation equal to 0.

    One value is d = 0. If d = 0 then left side will become 0 and we'll have 0 = 0. So thats one answer

    another value is d = 3. if d = 3, then the bracket (3-3) will give us 0 and 0 multiplied by anything is 0.

    So the answer is : d = 0 and d = 3

    For these kind of equations, the idea is to find for which value the equation will balance. (left side = right side).

  • 9 years ago

    factor it, i.e. take "7d" out of both of them because it is the highest amount that you can divide by in both of them


    can you take it from there buddy? solve 7d for zero, and solve d-3 for zero

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