how to solve quadratic equations by factoring

Question

6n^2-18n-18=6

Answer 1

 

You need to break this out into terms

 

6n^2 -18n -18 = 6

 

6n^2 - 18n -24 = 0   (get into standard form where a = 6  b = -18 and c = -24)

 

Need to find number that add up to 18 - and mutiply to 144   (take 6 * 24 = 144)

 

These numbers are 6 asn 24 - so you can re-write as

 

6n^2 - 24n + 6n -24 = 0

 

regroup (6n^2 - 24n) + (6n-24) = 0

 

factor out 6n from first term  and just 6 from second term

 

6n(n-4) + 6(n-4)

 

now factor out the (n-4)

 

(n-4) (6n + 6)

 

check: mult baxk

 

6n^2 +6n -24n -24  check

Answer 2

6n² - 18n - 18 = 6

6n² - 18n - 24 = 0

6(n² - 3n - 4) = 0

6(n - 4)(n + 1) = 0

 

{-1, 4}