Question

 If 11x +3y =28 and 3x + 11y =14 then x +y​

Answer 1

Answer:

x+y=9

Step-by-step explanation:

11x+3y=28 ------>1

3x+11y=14------->2

multiply 3 with eq 1

and

multiply 11 with eq 2

3(11x+3y=28)=33x+9y=84

11(3x+11y=14)=33x+121y=154

-112y=-70

112y=70

y=70/112

y=35/56=5/8

y=5/8

substitiute y value in eq 2

3x+11y=14

3x+11(5/8)=14

3x+55/8=14

24x+55=112

24x=112-55

24x=57

x=57/24

then x+y

57/24+5/8

(57+15)/8

72/8

=9

x+y=9