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Factor trinomials by grouping?

How do you factor these two separate equations?:


And also...


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Kelsy L. | Kelsy L.Kelsy L.
4.1 4.1 (16 lesson ratings) (16)

grouping is only effective with four expressions, for these you would use the Quadratic equation or the simpler method. first fine factors of the a and c values. So for 6 the factors are 1,2,3,6 and 57 is 1,3,19,57. then you multiply the factors so that the result would give a sum equal to the b value which is 1.

so for 6 use: 6 and 1. and for 57 use -3 and 19. 6*-3=18. 1*19 = 19. 19+(-18)=1. so the factor is (6x+19)(x-3).

the second equation you should factor out 2, because it's the highest common factor for each expression so

(2x^2 - 2x - 12)/2 =x^2 -x -6. then you do the factoring like in the first problem. for 1 factor is 1 and for 6 factors are 1,2,3,6. the sum should be equal to -1. so its 1*-3=-3 and 1*2=2. factor should be (x+2)(x-3)