(2x+/- )(x+/-) since 2 and 5 are prime experiment (2x+5)(x-1)=2x^2+5x-2x-5=2x^2+3x-5 nope (2x-1)(x+5)=2x^2-x+10x-5=2x^2+9x-5, yup
complete the square
first group x terms (x^2+8x)-5 take 1/2 of 8 and squaer it 8/4=4, 4^2=16 add negative and positive inside (x^2+8x+16-16)-5 factor perfect square ((x+4)^2-16)-5 distribute (x+4)^2-16-5 (x+4)^2-21
