Q.

The line passing through the point of intersection of x+y=2, x-y=0 and is parallel to x+2y=5 is ax+by=c, then value of a+b+c is _________.


Ans.

(6)

Required equation of line which is parallel to given line x+2y=5 is x+2y+k=0               …(i)

Given equations of lines are

          x+y=2                                                             …(ii)

          x-y=0                                                             …(iii)

Adding (ii) and (iii), we get 2x=2⇒x=1

Substituting x=1 in (iii), we get y=1

∴   Point of intersection is (1,1)

Substituting x=1, y=1 in (i), we get

1+2+k=0⇒k=-3

∴   Required equation of line is x+2y=3

Here, a=1, b=2 and c=3

∴  a+b+c=1+2+3=6