Question

solve the pair of linear equation 2x+y=40 and x+y=30 and if the solution is satisfies y=mx+6 find m.

Answer 1

hola!

x + y = ----(i)
2x + y = 40. ----(ii)

For eqn. (i) :-

x + y = 30
x = 30 - y. -----(iii)

Substituting value of eqn. (iii) in eqn (ii)

2(30-y) + y = 40

60 - 2y + y = 40

60 - y = 40

y = 60 - 40 = 20

Substituting y = 20 in eqn. (i)

x = 30 - 20 = 10

Hence,
( x, y ) = (10, 20) is the solution of linear eqn. in two variables.

Now,

Substituting (x, y) in y = mx + 6

20 = m(10) + 6

10m = 20 - 6

10m = 14

m = 14/10 = 1.4

Hence, The required solution is :-
m = 1.4

hope it helps! :)