Question:

2x^2= 7x - 3............... Factoring?

by Guest64919  |  earlier

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please explain how to do this problem.

i know......

2x^2 - 7x +3 = 0

right??

then i don't know the next step, please help and explain how you do it. thank you

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4 ANSWERS


  1. Start with the following....

    (2x +  A)(x + B )

    Using FOIL (first, outside, inside, last) for multiplication as your guide,

    try to think of two numbers such that

    2*B + A = -7

    and

    A*B = 3

    The second part is easy, since 3 is prime, and positive, the options are

    (1 and 3) or (-1 and -3)

    so try

    (2x - 1)(x - 3)

    Multiply using FOIL

    2x*x + (-1)*x + 2x*(-3) + (-1)(-3)

    2x^2 - 7x + 3

    So your answer is

    (2x - 1)(x - 3) = 0

    With practice, you'll get faster.


  2. correct.  The next step is to factor it into a format of (ax+b)(cx+d), where

    ac = 2

    ac +bd = -7

    cd = 3

    (2x-1) (x-3)

  3. (2x-1)(x-3)

  4. When you factor you inow your formula will be of the form

    ( Ax   +  b)(Cx + d)= 0

    from you equation you see that A*C=2. the only integers that will satis that are 2 and 1 by substituting for A and C

    (2x + b)(1x + d)=0

    now to find b & d: b*d=3 so either b=1(plus or minus) and d=3(Plus or minus) or vice versa

    we know that b + 2d = -7

    d has to be either -3 or -1 and to satisfy this equation, d can only = -3

    so b has to be -1

    (2x - 1)(x - 3)=0

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