FOIL method

[jdalla]

Multiply using FOIL ( x - 1/4) ( x -1/2 )

i'm confused with these fractions..any help would be appraciated

 

[BigGlenntheHeavy]

\(\displaystyle \bigg(x-\frac{1}{4}\bigg)\bigg(x-\frac{1}{2}\bigg) \ = \ x^2-\frac{x}{2}-\frac{x}{4}+\bigg(\frac{-1}{4}\bigg)\bigg(\frac{-1}{2}\bigg)\)

\(\displaystyle = \ x^2+\frac{-2x-x}{4}+\frac{1}{8} \ = \ x^2-\frac{3x}{4}+\frac{1}{8}\)

 

[jdalla]

this is a big help, thanks very much, i was confused with combining the -1/2 with the -3/4. I'm sure this is remedial stuff to guys like you

 

[Denis]

Multiply using FOIL ( x - 1/4) ( x -1/2 )

This way may make it less confusing to someone learning:
let a = 1/4 and b = 1/2 ; then:
(x - a)(x - b)
= x^2 - bx - ax + ab
= x^2 -x(a + b) + ab ; now substitute back in:
= x^2 -x(1/4 + 1/2) + (1/4)(1/2)
= x^2 - x(3/4) + 1/8

Get it?