The sum of two numbers is 9 and their product is 20.Find the sum of their squares and cubes.
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Answered by
89
let two numbers are a and b
(a+b)²= a²+b²+2ab
9²= a²+b²+2*20
81=a²+b²+40
81-40=a²+b²
41=a²+b²
(a+b)³= a³+b³+3ab(a+b)
9³= a³+b³+3*20(9)
729=a³+b³+540
729-540=a³+b³
189=a³+b³
please mark it as brainlist
(a+b)²= a²+b²+2ab
9²= a²+b²+2*20
81=a²+b²+40
81-40=a²+b²
41=a²+b²
(a+b)³= a³+b³+3ab(a+b)
9³= a³+b³+3*20(9)
729=a³+b³+540
729-540=a³+b³
189=a³+b³
please mark it as brainlist
Answered by
30
let the numbers be a&b
a+b=9
ab=20
a^2+b^2=(a+b)^2-2ab
=(9)^2-2(20)
=81-40
a^2+b^2 =41
the sum of the squares is 41.
a^3+b^3=(a+b)^3-3ab(a+b)
=(9)^3-3(20)(9)
=729-540
a^3+b^3=189
sum of their cubes ie 189.
a+b=9
ab=20
a^2+b^2=(a+b)^2-2ab
=(9)^2-2(20)
=81-40
a^2+b^2 =41
the sum of the squares is 41.
a^3+b^3=(a+b)^3-3ab(a+b)
=(9)^3-3(20)(9)
=729-540
a^3+b^3=189
sum of their cubes ie 189.
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