Question 193039: How do you solve:(y+1)(y-3)(y-4)? Also:(x+1)(x+1)(x+1)? Using the FOIL and then the vertical methods?
Answer by RAY100(1637)   (Show Source):
You can put this solution on YOUR website! exactly right
lets review
(y+1)(y-3)(y-4)
foil ist 2 terms
(y^2 -3y+y-3)(y-4)
(y^2-2y-3)(y-4)
rearrange, commutative property
(y-4)(y^2-2y-3)
now use distribution
(y)(y^2-2y-3) - (4)(y^2-2y-3)
y^3-2y^2-3y -4y^2+8y+12
combine like terms
y^3-6y^2+5y+12 ANSWER
Yes we prefer vertical allignment, but extremely hard to type
check let y=0,,,original 1*-3*-4=12
answer,,,,12=12 ok
check again with y=1
original,,,2*-2*-3=12
answer,,,,1-6+5+12=12 ok
again, with practice this moves right along
(x+1)(x+1)(x+1)
(x+1)(x^2+2x+1)
x(x^2+2x+1)+1(x^2+2x+1)
x^3 +2x^2+x +x^2+2x+1
x^3 +3x^2+3x+1 ANSWER
check using y=0
0riginal ,,,1 answer,,,1,,,,ok
with y=2
answer,,,27,,,answer8+12+6+1=27
KEEP UP the good work,,,,it just takes a little practice
|
|
|
