factor 15x2 - 31x + 2

Question

factor by grouping i don't understand how to do it

Answer 1

Factors of 15 are 3 and 5, and 1 and 15; and the factors of 2 are 2 and 1, so when factorised we will have (3x-1)(5x-2), or (3x-2)(5x-1), or (15x-1)(x-2) or (15x-2)(x-1). The middle term is going to be the sum of cross-products (31). The solution must be (15x-1)(x-2).

Answer 2

15x^2 -31x+2=0

me yuze quadratik equashun...roots=[-b +-sqrt(b^2-4ac)]/2

roots=2 &0.0666666666666...

=2 &2/30