Megan factored the expression 18x^2 - 57x + 35 as (6x -7 )(3x-5) . But when Jacob applied the FOIL principle and multiplied out (6x -7 )(3x-5), he got 18x^2 -51x+35; thus, Megan’s solution does not appear to check. Why is that? Please help Megan to understand this better. Explain your reasoning and correctly factor the original expression, if possible. If the expression is prime, so state. (Points : 6)

Question

amistre64 · Answer

the reason why foil can fail to work is becasue you are trying to remember how to multiply when you already know how to multiply

anonymous · Answer

18x^2 - 57x + 35 as (6x -7 )(3x-5) , here we see that Megan didnt factor correctly,

anonymous · Answer

the "foil principle"??
no wonder megan is innumerate.  look at her teacher.

anonymous · Answer

18^2 - 57x + 35 can be simplified into
18^2 - 42x - 15x + 35
6x(3x - 7) - 5(3x - 7)
(6x - 5)(3x-7)

Megan may have tried to take shortcuts and do it in her head - it's always better to work it out in full :)

amistre64 · Answer

6x -7
   3x -5
--------
18x^2 -21x
           -30x +35
----------------
18x^2 -51x +35

amistre64 · Answer

I like it that "when Jacob applied the FOIL principle" he got it absolutely right .... talk about brainwashing lol

anonymous · Answer

exactly, amistre :)