Question

20/x+y +3/x-y =7 and 8/x-y -15/x+y =5 by elimination method

Answer 1

Answer:

x=3, y=2

Step-by-step explanation:

Consider A= 1/ x+y, B=1/ x-y,

Therefore, 20A+3B=7 [eq.1]     , -15A+8B=5[eq.2]

Multiply eq.1 by 3,  60A+9B=21

Multiply eq.2 by 4, -60A+32B=20  [+]

                                 0 A+ 41B= 41

                                  B=1,

Substitute B=1 in eq.1,

     20A+3[1]= 7, 20A=4, A=1/5......

Equate for A & B,

A=1/x+y,   1/5=1/x+y, x+y=5

B=1/x-y,    1=1/x-y, x-y=1. x=y+1......

Substitute x value in x+y=5,

We get x=3 and y=2