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
31
Timethe numbers are 5 and 4. so the sum of their squares is 25 + 16 which is equal to 41. and the sum of their cubes is 125+ 64 which is equal to 189
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45
xy=20 eq1
x+y=9
x=9-y
substitute value of x in eq1
xy=20
(9-y)y=20
9y-y^2=20
20-9y+y^2=0
y^2-9y+20=0
y^2-5y-4y+20=0
y(y-5)-4 (y-5)=0
(y-5)(y-4)
y=5 or y=4
x+y=9
x=9-y
substitute value of x in eq1
xy=20
(9-y)y=20
9y-y^2=20
20-9y+y^2=0
y^2-9y+20=0
y^2-5y-4y+20=0
y(y-5)-4 (y-5)=0
(y-5)(y-4)
y=5 or y=4
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