Question

Factor Completely
21x^2 + 31x + 4

Answer 1

lotta choices

Answer 2

( 7 + 2 ) ( 2+ 2 )

Answer 3

i would go with \((7x+...)(3x+...)\) and see what words

Answer 4

is that the answer ? factoring what ?

Answer 5

this is a pain
two numbers whose product is 4, could be 1 and 4 or 2 and 2, but you need the sum to be 31 which is odd, so 2 and 2 is out
find the right place to put the 1 and 4

Answer 6

answer is easy enough to come by, but trial and error is the method

Answer 7

http://www.wolframalpha.com/input/?i=21x^2+%2B+31x+%2B+4

Answer 8

21x^2 + 31x + 4
= 21x^2 + 3x + 28x + 4
= 3x ( 7x +1) + 4 (7x+1)
= (3x+4)(7x+1)