Question

How do you factor the expression 12x² - 21x + 3?

Answer 1

`12(x-(7+sqrt(33))/8)(x-(7-sqrt(33))/8)`

Explanation:

First let's factor
`3(4x^2-7x+1)`
Then find the zeroes for
`4x^2-7x+1`
`x=(7+-sqrt(7^2-4*4*1))/(2*4)`
`x=(7+-sqrt(33))/8`
then we can factor again:

`3*4(x-(7+sqrt(33))/8)(x-(7-sqrt(33))/8)`
or
`12(x-(7+sqrt(33))/8)(x-(7-sqrt(33))/8)`