(a-b)=3 and ab=5 then a3-b3=
Answers
Answered by
5
Answer:
(a-b)³=a³-b³-3ab(a-b)
now substitute the given value in the equation
(3)³=a³-b³-3.5.(3)
27=a³-b³-45
a³-b³= 27+45
a³-b³= 72
Answered by
1
Answer:
(a-b)=3
cubing both sides
(a-b)^3=(3)^3
(a-b)(a^2+b^2-2ab)=9
(a-b)(a^2+b^2-2*5)=9
(a-b)(a^2+b^2-10)=9
a^3+ab^2-10a-a^2b-b^3+10b=9
a^3-b^3-10 (a-b)+ab^2-a^2b=9
a^3-b^3-10*3-a^2b+ab^2=9
a^3-b^3-30-ab (a-b)=9
a^3-b^3-30-5*3=9
a^3-b^3-30-15=9
a^3-b^3-45=9
a^3-b^3=9+45
a^3-b^3=54.
Hope it will help you.
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