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How do you factor the trinomial #3r^2+2r-21#?

Answer 1

#(3r -7)(x + 3)#

If a trinomial can be factored, the factors of #(ax + b)(cx + d)# will give #acx^2 + (ad +bc)x + bd#. We therefore need factors of #3# and #-21# that will combine to give #2#. The only possible factors of #3# are #3# and #1#. The appropriate factors of #-21# are #-7# and #3# #3r^2 +2r - 21 = (3r -7)(x + 3)#

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Answer 2

Hazel Anglin

To factor the trinomial 3r^2 + 2r - 21, you can use the quadratic formula or factoring by grouping method. The factored form is (3r - 7)(r + 3).

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.