Question

If 31x+43y=117 and 43x+31y=105 then the value of x + y is ​

Answer 1

Answer:

$31x + 43y = 117\\\\31x = 117 - 43y$

$x = \frac{117 - 43y}{31}$                                 ..........................(equation 1)

$43x + 31y = 105$

putting the value of x from equation 1

$43( \frac{117 - 43y}{31}) + 31y = 105 \\\\( \frac{5031 - 1849y + 961y}{31}) = 105\\\\5031 - 1849y + 961y = 105 * 31\\\\5031 - 888y = 3255\\\\-888y = 3255 - 5031\\\\-888y = - 1776\\\\y = \frac{1776}{888}\\\\y = 2$

now putting the value of y in equation 1 to find x

$x = \frac{117 - 43(2)}{31}\\\\x = \frac{117 - 86}{31}\\\\x = \frac{31}{31}\\\\x = 1$

now finding x + y

i.e 1 + 2 = 3

Answer 2

Answer:

X+y

1+2=3

3 is the answer