Question

If 12x + 13y = 29 and 13x + 12y = 21, find x + y.​

Answer 1

12x + 13y = 29

13x + 12y = 21

____________ [GIVEN]

• We have to find the value of x + y.

______________________________

» 12 x + 13 y = 29 _______ (eq 1)

» 13x + 12y = 21 ________ (eq 2)

Multiply (eq 1) by 13 and (eq 2) by 12.

12 x + 13 y = 29 (× 13)

=> 156x + 169y = 377 ______ (eq 3)

13x + 12y = 21 (× 12)

=> 156x + 144y = 252 _______ (eq 4)

• Subtract (eq 4) from (eq 3)

=> 156x + 169y - (156x + 144y) = 377 - 252

=> 156x + 169y - 156x - 144y = 125

=> 25y = 125

=> y = 5

• Put value of y in (eq 1)

=> 12x + 13(5) = 29

=> 12x + 65 = 29

=> 12x = 29 - 65

=> 12x = - 36

=> x = - 3

______________________________

• We have to find the value of x + y.

From above calculations we have x = -3 and y = 5

x + y = - 3 + 5

x + y = 2

______________________________

$\textbf{x + y = 2}$

_____________ [ANSWER]

Answer 2

Answer:

X+Y=2

Step-by-step explanation:

12x+13y=29______1st. eq..

13x+12y=21_______2nd. eq..

_______________________

25x+25y=50 ( by adding)

x+y=2 { dividing both side by 25}

HOPE IT WILL HELP YOU