Question

find the values of (x+y)and (x-y) if 4x+3y=11 ; 3x+4y=10​

Answer 1

Answer:

3x+4y=10 .......... (1)×3

4x+3y=11.............(2)×4

3x×3+4y×3=10×3

4x×4+3y×4=11×4

9x+12y=30........(3)

16x+12y=44.......(4)

- - - subtract

______________________

-7x =-14

X=-14÷-7

X=2

Put x=2 in eq. (1)

3x+4y=10

3×2+4y=10

6+4y=10

4y=10-6

4y=4

Y=1

(x,y)=(2,1)

There for (x+y) =2+1=3

(x-y) =2-1=1