Question

If 13 x + 7 y = 33 and 7 x + 13 y = 47 then the value of x + y = ________

(4, 17.5, 70, 80 )​

Answer 1

Answer:

13x+7y=33. —i)

7x+13y=47. —ii)

On multiplying i) by 7 and ii) by 13 and subtracting them we get :

91x+49y-91x-169y=231-611

= -120y = -380

=120y = 380

=y=380/120

=y=19/7.

Putting the value of y in i),we get:

13x+19=33

=13x=33-19

=13x=14

=x=14/13.

Step-by-step explanation:

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