Question

If ax+20y=20 and 5x-by+10=0 are coincident lines then a+b=?​

Answer 1

Answer:

ax + 20y = 20

5x - by = -10

-_____________

x ( a-5) + y ( 20+b ) = 30

(x+y) ( a-5 + 20+ b) = 30

(x+y) ( a+b +15) =30

×+y = 30

a+b=30-15

a+b=15 ______ans