The problem
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i dont understand how x(x-7)+4(x-7) become (x-7)(x+4)
Answer provided by our tutors
Factoring out common terms can appear in many different situations. For example, "2x+3x" could be factored out into "(2+3)x" since both the '2' and the '3' had the common factor 'x'. So in your problem (appended to this reply) is a common factor (x-7) which can then allow the 'x' and '+4' terms be factored into (x+4).
