Question

Slove the following pairs of equation 39x+41y=76 , 41x+39y=84

Answer 1

AnswEr

The values are

x = 3

y = -1

Solution

Given the equations are

39x + 41y = 76_______(1)

41x + 39y = 84_______(2)

Subtracting (1) from (2) we have,

⇒41x + 39y - 39x - 41y = 84 - 76

⇒ 2x - 2y = 8

⇒ x - y = 4

⇒x = 4 + y __________(3)

Putting the value of x in equation (1)

⇒39(4 + y) + 41y = 76

⇒ 156 + 39y + 41y = 76

⇒80y = -80

⇒y = -1

Now putting the value of y in (3) we have

⇒x = 4 + (-1)

⇒x = 4 - 1

⇒x = 3

Answer 2

ANSWER:

• x = 3
• y = (-1)

GIVEN:

• 39x + 41y = 76
• 41x + 39y= 84

TO FIND:

• Value of 'x' and 'y'

SOLUTION:

=> 39x + 41y = 76. .......(i)

=> 41x + 39y= 84. ........(ii)

Adding eq (i) and (ii) We get;

=> 39x+41x +41y+39y = 76 +84

=> 80x+80y = 160

=> 80(x+y) = 160

=> x+y = 160/80

=> x+y = 2. ........(iii)

Subtracting eq (i) from (ii) we get;

=> 41x+39y -(39x+41y) = 84-76

=> (41x-39x) + (39y -41y) = 8

=> 2x -2y = 8

=> 2(x-y) = 8

=> x-y = 8/2

=> x-y = 4. ......(iv)

Adding eq (iii) and (iv) we get;

=> x+y+x-y = 4+2

= 2x = 6

=> x = 6/2

=> x = 3

Putting x = 3 in equation (iii) we get;

=> 3 + y = 2

=> y = 2-3

=> y = (-1)