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anonymous
 4 years ago
how would i factor 8x^2 + 2x 21
anonymous
 4 years ago
how would i factor 8x^2 + 2x 21

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sasogeek
 4 years ago
Best ResponseYou've already chosen the best response.2multiply the coefficient of the x^2 term by the constant and find 2 factors of the result that when you add or subtract will give you the x coefficient, replace the x coefficient with the two factors in a way that when you subtract or add them, you'll get the x coefficient. you'll get 4 terms. take the first two terms and factor them, take the last two terms and factor them. you're done. if you didn't understand what i've just written, read it carefully again, take your time, and solve it.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0You can use the quadratic equation formula (b +orsqrt(b^24ac))/2a here a,b,c are the coefficients ax^2+bx+c

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0understood? @alexeis_nicole

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0yep.. i got 24 and 26... :S ?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0I MEAN ... 1.5 AND 1.75?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Quadratic Formula in an easiertoread form: \[x=\frac{b\pm \sqrt{b^24ac}}{2a}\] Binomials will be written as (where a, b, and c are numerical constants) \[ax^2 + bx + c\] You can always check your factorization by multiplying it back together to get the original expanded form (what you have initially here).

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.01.5 and 1.75 are correct, but put them in fraction form and you'll have a huge hint ;)

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Huge hint: \[\frac {numerator}{demominator} = \frac {c}{a}\]

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0(ax+c)(ax+c) (but different a's and c's, call them a1 & c1 and a2 & c2 if you want)

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Here's one of the two, so you're not getting confused: 7/4 > (4x+7)

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Here's how to check, solve this: \[4x+7 = 0 \]

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0OH !!!!! (2x3) (4x+7)

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Do you see why the /+ sign switches?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0So here's the next step they'll probably introduce you to later, they'll ask you to solve this: \[8x^2 + 2x 21 = (2x3)(4x+7) = 0\]
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