Question

if t-u =3 and ut= -1.find the value of t³-u³​

Answer 1

Solution,

given,

t-u=3

u.t= -1

$t^3-u^3=?$

now,

Implementing the formulas and values of particular terms to find value of $t^3-u^3$, we get;

:. $t^3-u^3$$t^3-u^3= (t-u)(t^2+u.t+u^2)\\ = (t-u)[(t)^2+(u)^2+u.t]\\ = (t-u)((t-u)^2+2.u.t+u.t]\\ = (t-u)[(t-u)^2+3.u.t]\\\\ =(3)[(3)^2+3.(-1)]\\ = (3)[9-3]\\ =3.(6)\\ = 18$