You can
put this solution on YOUR website!this is the difference of two squares ___ two perfect squares with a minus in between
the square root of 9c^2 is 3c
the square root of 121 is 11
the factors are (3c+11)(3c-11)
the difference in the signs results in the middle term of the FOILed product being zero (try it!)
You can
put this solution on YOUR website!factoring is recognition of patterns
a^2-B^2 = (a+b) (a-b)
9C^2 -121= (3c)^2 -(11)^2= (3c+11)(3c-11)
checking by foil
(3c+11)(3c-11)
9c^2 -33c+33c-121= 9c^2-121
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