Question

substitution method: 2x-y=4, x+2y=7

Answer 1

Ok. First 2x=y+4

then x= (y+4)/2

from this point ;
substitute this value to the second question ;

(y+4)/2 +2y =7 then

equalise the denominators. it will be like
(5y + 4 ) / 2 = 7

then solve y . which is

14 = 5y + 4
10 = 5y
y = 2

then substitute y into the equations like
x +2y = 7 then
x + 4 = 7
x= 3

thats all :D