Answer:
The numbers are 8 , 5 , 1
Explanation:
Let the three numbers be x,y,z
Sum of three numbere is 14
⇒ x +y + z = 14 ---------------(I)
The sum of twice the first number, 4 times the second number, and 5 times the third number is 41. 
⇒ 2x + 4y + 5z = 41 -----------(II)
The difference between 7 times the first number and the second number is 51.
⇒ 7x -y = 51 ---------------(III)
Multiply equation (I) by (-5) and then add this wiht equation (II). Thus 'z' will be eliminated.
(I)*(-5) -5x - 5y - 5z = -70
(II  2x + 4y + 5z = 41 {Now add}
 -3x - y = - 29 ------------(IV)
Multiply (III by (-1) and then add it with equation (IV)
(III)*(-1) -7x + y = -51
(IV)  -3x - y = -29  {Now add}
  -10x = -80
 x = -80 ÷ (-10)
x = 8
Plugin x = 8 in equation (III) and we obtain the value of y
7*8 - y = 51
 56 - y = 51
 -y = 51 - 56
 -y = -5
 y = -5 ÷ (-1)
y = 5
Plugin x =8 and y =5 in equaiton (I)
8 + 5 + z = 14
 13 + z = 14
 z = 14 - 13
 z = 1