The product of two numbers is 12 .. If their sum added to the sum of their squares is 32, find the numbers ???? plzzz solve it fast...
Answers
Answered by
22
let 1st number is X and other number is y
given
XY= 12
given
XY= 12
Anonymous:
but how these 56 came
Answered by
42
Product of numbers = 12
Possibilities (1,12) , (2,6), (3,4)
Sum of number + sum of squares = 32
Hence 1st and second combinations aren't possible.
So the numbers are 3,4
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Let the numbers be a & b
Given,
a*b = 12
a+b + (a^2+b^2) = 32
.............................................
(a^2+b^2) = (a+b)^2 - 2*a*b [identity]
(a+b) + (a+b)^2 - 2*a*b = 32
(a+b) + (a+b)^2 - 2*12 = 32
(a+b) + (a+b)^2 = 56
(a+b)^2 + (a+b) - 56 = 0
(a+b)^2 + 8(a+b) - 7(a+b) - 56 = 0
(a+b)*[(a+b) + 8] - 7*[(a+b) + 8] = 0
[(a+b) +8]*[(a+b)-7] = 0
a+b = 7
ab = 12
b = 12/a
a + 12/a = 7
a^2 + 12 = 7a
a^2 - 7a + 12 = 0
(a-4)*(a-3) = 0
a=4 or 3
So if a = 3, b=4
Hence numbers are 3,4
Hope it helps.
Possibilities (1,12) , (2,6), (3,4)
Sum of number + sum of squares = 32
Hence 1st and second combinations aren't possible.
So the numbers are 3,4
--------------------------------------------------------------------------------------------
Let the numbers be a & b
Given,
a*b = 12
a+b + (a^2+b^2) = 32
.............................................
(a^2+b^2) = (a+b)^2 - 2*a*b [identity]
(a+b) + (a+b)^2 - 2*a*b = 32
(a+b) + (a+b)^2 - 2*12 = 32
(a+b) + (a+b)^2 = 56
(a+b)^2 + (a+b) - 56 = 0
(a+b)^2 + 8(a+b) - 7(a+b) - 56 = 0
(a+b)*[(a+b) + 8] - 7*[(a+b) + 8] = 0
[(a+b) +8]*[(a+b)-7] = 0
a+b = 7
ab = 12
b = 12/a
a + 12/a = 7
a^2 + 12 = 7a
a^2 - 7a + 12 = 0
(a-4)*(a-3) = 0
a=4 or 3
So if a = 3, b=4
Hence numbers are 3,4
Hope it helps.
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