Question

2x+3y=13 and 2x-3y=-5 solve by Substitution method

Answer 1

if 2x+3y=13

2x-3y=-5

4x=8


  x=2   by substituting the value of x in the above equation 

we get y as 3

Answer 2

2x+3y=13
⇒2x=13-3y  ⇒x=(13-3y)/2....(i)

Also,
2x-3y=-5
2(13-3y)/2 -3y=-5           ∵[from i]
13-3y-3y=-5
13-6y=-5
-6y=-5-13   ⇒-6y=-18   ⇒y=-18/-6=3
∴y=3

Then from (i),
x=(13-3y)/2
x=13-3(3)/2
x=(13-9)/2  =4/2 =2

∴x=2,y=3