x+y=3,xy=2 so find x³-y³=?
Answers
Answered by
15
x+y=3,xy=2
so x-y = root over of (x+y)^2-4xy = root over of 3^2-4×2=root over of 1=1
x-y=1
then
x^3-y^3=(x-y)(x^2+xy+y^2)=1[(x^2+2xy+y^2)-xy] = 1[(x+y)^2-xy]
=3^2-2=9-2=7
so the ans is 7
hope you get your ans
please mark me as Brainliest if you get this
so x-y = root over of (x+y)^2-4xy = root over of 3^2-4×2=root over of 1=1
x-y=1
then
x^3-y^3=(x-y)(x^2+xy+y^2)=1[(x^2+2xy+y^2)-xy] = 1[(x+y)^2-xy]
=3^2-2=9-2=7
so the ans is 7
hope you get your ans
please mark me as Brainliest if you get this
Answered by
5
Answer:
7
Explanation:
As x+y=3
let x & y be 2 & 1 respectively
so, 2+1 = 3
2*1=2
as this proves right that x = 2 & y = 1
lets replace x³-y³ with the above numbers
which will give
= 2³ - 1³
= (2*2*2) - (1*1*1)
= 8 - 1
= 7
∴ x³-y³
= 2³ - 1³
=7
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