if (a+b,a-b)is the solution of the equtions 3x+2y=20and 4x-5y=42 then find the value of b
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3x+2y=20.......(1)*5
4x-5y=84.........(2)*2
15x+10y=100
8x-10y=84
..........................
23x=184
x=184/23=8
then
3*8+2y=20
y=-2
therefore
a+b=8
a-b=-2
...............
2a=6
a=3
therefore
b=8-3=5
4x-5y=84.........(2)*2
15x+10y=100
8x-10y=84
..........................
23x=184
x=184/23=8
then
3*8+2y=20
y=-2
therefore
a+b=8
a-b=-2
...............
2a=6
a=3
therefore
b=8-3=5
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