mzapata29
Not understanding how to work sum of cubes 125x^3+27y^3



This Question is Open

matricked
Best Response
You've already chosen the best response.
0
do u need to factor them

matricked
Best Response
You've already chosen the best response.
0
then use a^3+b^3= (a+b)(a^2 ab+b^2)

matricked
Best Response
You've already chosen the best response.
0
for a^3b^3= (ab)(a^2 +ab+b^2)

agent0smith
Best Response
You've already chosen the best response.
0
\[ 125x^3+27y^3 = (5x)^3 + (3y)^3\]

matricked
Best Response
You've already chosen the best response.
0
if u need not factor them then use
a^3+b^3 =(a+b)^3 3ab(a+b)

agent0smith
Best Response
You've already chosen the best response.
0
Now a = 5x and b =3y.

matricked
Best Response
You've already chosen the best response.
0
125x^3+27y^3 =(5x)^3 +(3y)^3
=(5x+3y)(25x^2 15xy +9y^2)