If (x - y) = 7, then what is the value of $$(x-15)^{3}-(y-8)^{3}$$ ?
To find : $$(x-15)^{3}-(y-8)^{3}$$
Let $$(x-15)=a$$ and $$(y-8)=b$$
Thus, we need to find : $$a^3-b^3$$ -----------(i)
=> $$x=a+15$$ and $$y=b+8$$ ---------(ii)
It is given that, $$(x-y)=7$$
Substituting values from equation (ii),
=> $$(a+15)-(b+8)=7$$
=> $$a-b+7=7$$
=> $$a-b=0$$
Cubing both sides, we get :
=> $$a^3-b^3-3ab(a-b)=0$$
=> $$a^3-b^3-3ab(0)=0$$
=> $$a^3-b^3=0$$
=> Ans - (A)
Create a FREE account and get:
