SOLUTION: I am trying to factor this expression as if I did not know the form of a difference of squares. Where is my error? 4x^2-49 4x^2 + 14x - 14x - 49 (4x^2 + 14x) + (- 14x - 49)

Algebra ->  Expressions -> SOLUTION: I am trying to factor this expression as if I did not know the form of a difference of squares. Where is my error? 4x^2-49 4x^2 + 14x - 14x - 49 (4x^2 + 14x) + (- 14x - 49)      Log On


   

Question 1065838: I am trying to factor this expression as if I did not know the form of a difference of squares.
Where is my error?
4x^2-49
4x^2 + 14x - 14x - 49
(4x^2 + 14x) + (- 14x - 49)
2x(x+7) + -7(x+7)
(2x-7)(x+7)
However (2x-7)(x+7) = 2x^2-49 not 4x^2-49
Where is my error?
Found 3 solutions by Boreal, Fombitz, addingup:
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
(4x^2 + 14x) + (- 14x - 49)
When you factor this, you get
2x(2x+7)-7(2x+7)=(2x-7)(2x+7)
If you look at the second term, it is -14x-49.
You divided 7 into 14 and got 1 :)

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
%284x%5E2+%2B+14x%29+%2B+%28-+14x+-+49%29
2x%282x%2B7%29-7%282x%2B7%29<--- Left out a 2 in the right hand term
%282x-7%29%282x%2B7%29

Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
There is only one step.
Factor 4x^2-49
------------
4x^2 factors into:
(2x )(2x )
Next:
-49 factors into:
( -7)( +7)
All together:
(2x-7)(2x+7)