8a^3 + c^3 =?

a. (2a+c)(2a+c)(2a+c)


b. (2a-c)(4a^2+2ac+c^2)


c. (2a-c)(4a^2+4ac+c^2)


d. (2a+c)(4a^2-2ac+c^2)





3. What equivalent to x^3-y^3/x^2-y^2





a. x-y


b. x+y


c. x^2+xy+y^2/x+y


d. x^2-xy+y^2/x-y

8a^3 + c^3 =?
3.


a. x-y
Reply:first on is D due to the sum of two perfect cubes


The second one well umber 3 is a whan dividing powers subtract the powers
Reply:1. x^3 + y^3 = (x+y)(x^2-xy+y^2)


So - 8a^3 + c^3 = d. (2a+c)(4a^2-2ac+c^2)





3. a^3 – b^3 = (a – b)(a^2 + ab + b^2)


So





x^3-y^3/x^2-y^2


(x – y)(x^2 + xy + y^2) / (x - y)(x + y)


(x^2 + xy + y^2) / (x + y)





D
Reply:well, i'm not going to do it for you. let's see. for the first one,


a^3+b^3= (a+b)(a^2 - ab + b^2)


8a^3=(2a)^3





for the second one


a^3-b^3=(a-b)(a^2+ab+b^2)


a^2-b^2=(a+b)(a-b)


then cancel out





hope that helps =)
Reply:1) as (x^3 + y^3) = (x+y)(x^2 - xy + y^2)





so 8a^3 + c^3 = (2a + c)(4a^2 - 2ac + c^2 )


so ans is d





2) d





sameapprocah as 12 and (x^2-y^2) = (x+y)(x-y) and cancelling x + y
Reply:1)


8a^3 + c^3


= (2a + c)(4a^2 - 2ac + c^2)


(answer d)





2)


(x^3 - y^3)/(x^2 - y^2)


= (x - y)(x^2 + xy + y^2)/(x - y)(x + y)


= (x^2 + xy + y^2)/(x + y)


(answer d)
Reply:hm..


let me answer this questions


for the first one you can reduce it too (2a+c)(4a^2-2ac+c^2)





for number 3..


d. x^2-xy+y^2/x-y