can you please answer this ...
Answers
Answer:
157
Step-by-step explanation:
Given---> m√m + n√n = 550
m√n + n√m = 549
To find---> 13 ( m + n ) / 7 = ?
Solution---> ATQ,
m√m + n√n = 550 ...............................(1)
m√n + n√m = 549 ...............................(2)
Let √m = x and √n = y
So, m = x² and n = y²
Now from equation ( 1 )
m√m + n√n = 550
=> x² ( x ) + y² ( y ) = 550
=> x³ + y³ = 550 ............................(3)
Now from equation ( 2 )
m√n + n√m = 549
=> x²( y ) + y² ( x ) = 549
=> xy ( x + y ) = 549...............................(4)
Now we know that,
( x + y )³ = x³ + y³ + 3xy ( x + y )
Putting values of (x³ + y³) and xy(x + y ) from equation (3) and (4) . we get
=> ( x + y )³ = 550 + 3 ( 549 )
= 550 + 1647
= 2197
=> ( x + y )³ = ( 13 )³
Taking cube root of both sides , we get
=> x + y = 13
Now from equation(4)
xy(x + y ) = 549
Putting x + y = 13 in it we get
xy ( 13 ) = 549
=> xy = 549 / 13
Now , we know that
( x + y )² = x² + y² + 2xy
=> ( 13 )² = x² + y² + 2 ( 549 / 13 )
=> 169 = x² + y² + ( 1098 / 13 )
=> x² + y² = 169 - ( 1098 / 13 )
Putting x = √m and y = √n , we get
=> ( √m )² + ( √n )² = (2197 - 1098) / 13
=> m + n = 1099 / 13
Now,
13(m + n ) / 7 = 13( 1099 / 13 ) / 7
13 is cancel out
= 1099 / 7
= 157
Given :-----
- m(√m) + n(√n) = 550
- m(√n) + n(√m) = 549
To find :------
- 13/7(m+n)
Formula used :-----
- (√a)² = a
- (x+y)³ = x³ + y³ + 3xy(x+y)
- (x+y)² = x² + y² + 2xy
See solution in image now ......
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[1] ( a + b )² = a² + 2ab + b²
[2] ( a – b )² = a² – 2ab + b²
[3] ( a + b )³ = a³ + 3a² b + 3ab² + b³
[4] ( a – b )³ = a ³ – 3a² b + 3ab² – b³
[5] ( a + b )( a ² - ab + b² ) = a³ + b³
[6] ( a – b )( a ² + ab + b² ) = a³ – b³