anonymous
  • anonymous
Explain, in complete sentences, how you would completely factor 20x2 – 28x – 48 by using the grouping method. How would you check your factors for accuracy?
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
chestercat
  • chestercat
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
bahrom7893
  • bahrom7893
I don't wanna write an essay... I can solve, not explain..
anonymous
  • anonymous
that would be fine too.
UnkleRhaukus
  • UnkleRhaukus
i would start with factoring out the 4

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

anonymous
  • anonymous
4(5x-12)(x+1)
anonymous
  • anonymous
you pull out the GCF first (which is 4), when you factor the trinomial. You can check you're answer by plugging in values for x... a nice value to use is like 1.
anonymous
  • anonymous
Thank you
anonymous
  • anonymous
np :)
anonymous
  • anonymous
bahroom - being able to explain a concept demonstrates the mastery ...
anonymous
  • anonymous
bridget - I'm a math teacher. Can you explain how to factor 5x^2 -7x -12 into (5x-12)(x+1) ? hint : there is an almost exact method for factoring trinomials with leading coefficients different than 1 !
bahrom7893
  • bahrom7893
mathg, LE CHALLENGE ACCEPTED (One O in my name)
bahrom7893
  • bahrom7893
Explain, in complete sentences, how you would completely factor 20x2 – 28x – 48 by using the grouping method. Okay, group like terms, usually like terms are the ones that have factors or coefficients in common
bahrom7893
  • bahrom7893
Pull out a 4 from the whole thing: 4(5x^2 - 7x - 6).. factor 5x^2 - 7x - 6 further, i never learned that shortcut where factors of something add up to something, so I've always used this brute force method (discriminant :) ) D = b^2-4ac = (-7)^2 - 4 * 5 * (-6) = 49 + 120 = 169 x1 = (-b-sqrt(D))/(2a) = (-(-7)-sqrt(169))/(2*5) = (7 - 13)/10 = -6/10 = -3/5 x2 = (-b+sqrt(D))/(2a) = (-(-7)+sqrt(169))/(2*5) = (7 + 13)/10 = 20/10 = 2 Factors: (x-x1)(x-x2)
bahrom7893
  • bahrom7893
So your equation factored becomes: 4(x-(-3/5))(x-2) or 4(x+(3/5))(x-2)
anonymous
  • anonymous
Ok ... bahroom I have a different method ... faster , I think .
anonymous
  • anonymous
find the product of the leading coefficient and the free term (a*c), in our case (5)*(-12)=-60 , b the coefficient of x is the sum (-7) . The task is to find two factors of (-60) that add up to (-7). After a bit of mental trial and error we can see the two factors we're looking for are -12 and 5 . Now rewrite the trinomial substituting -7x with -12x + 5x. 5x^2 +5x - 12x -12 - Factor by grouping : 5x(x+1)-12(x+1) and factor again the GCF (x+1)(5x-12) . QED
bahrom7893
  • bahrom7893
One O in my name
bahrom7893
  • bahrom7893
I thought math teachers paid attention to details
anonymous
  • anonymous
you made a mistake ... check your work ...
anonymous
  • anonymous
the 4(-6) ≠ -48
bahrom7893
  • bahrom7893
yes i did, tnx for letting me know

Looking for something else?

Not the answer you are looking for? Search for more explanations.