Question

The pair of equations X+Y=7 and X+Y+7=0 has
1)one solution
2)two solutions
3)no solution
4)Infinite number of solutions​

Answer 1

Let X + Y = 7 ........ i

X + Y + 7 = 0....... ii

in equation ii

X + Y = -7

X = -7 - Y ........... iii

Substituting iii in i we get

( -7 - Y ) + Y = 7

-7 - Y + Y = 7

-7 = 7

but they are not equal

so, the above set of equations do not have any no solution