Question

If x - y=4 and xy=45, find the value of x3-y3

Answer 1

Hey friend...

Here is your answer....

X-y=4

Y=X-4

Xy=45

X(X-4)=45

X^2 - 4X-45 = 0

X^2 - 9X + 5X - 45 =0

On solving,

X=9 or - 5 and Y=5 or - 9

Now,

X^3 - y^3 = 729-125

=604

X^3 - y^3 = - 125 + 729

= 604

HOPE that it will help you to understand.....

Follow me....

Plz mark it as brainliest answer.....

Answer 2

Hey there.....!!

We know that,

(x-y)^2 = x^2 + y^2 - 2*x*y

Substituting the values in the above formula we get the value of (x^2 + y^2)

(4)^2 = x^2 + y^2 - 2*45

16 = x^2 + y^2 -90

x^2 + y^2 = 106

Now,

x^3 - y^3 = (x-y) (x^2 + y^2 + xy)

Substituting by he values in the given formula⤵

x^3 - y^3 = (4) (106 + 45)

x^3 + y^3 = 4 * 151

x^3 + y^3 = 604✔

Hope this helps!!!