Question

If x²+y²=49 and x-y=3,then find the value of x³-y³

Answer 1

Answer:

Step-by-step explanation:

Given that,

x2+y2=49

x-y=3

We Know That,

(x-y)^2=x2-2xy+y2

=>3^2 =49-2xy

=>9=49-2xy

=>49-2xy=9

=>-2xy=9-49

=>-2xy= - 40

=>xy = -40 ÷ (-2)

=>xy = 20

By Putting the Value of x3-y3,

We get

x3-y3

=(x-y)(x2+y2+xy)

=3(49+xy)

=3×49+20

=3×69

= 207 (Ans)

Hope it helped you

Answer 2

Answer:

207

Step-by-step explanation:

given value is,x2 + y2 =49

x-y =3

then, (x-y) 2 =x2-2 xy + y 2

(3)2=39-2 xy

48-2xy=9

-2xy =9-49

-2xy= -40

xy= (-40)÷ (-2)

xy=20

let, the value be putted of x3-y3

so we get x3 -y3

and after solving we get 207 as our ans