Question

How do you solve by substitution 2x+y=9 and 4x−y=−15?

Answer 1

4x-y=-15

= 4x=y-15

= x= y-15/4

Thus put the value of x in other equation. Like this-

2x+y=9

= 2(y-15/4)+y=9

= y-15/2 + y=9

= y-15+2y/2=9

= - 15 + 3y= 18

= 3(-5+y)= 18

= - 5+y=6

= y=11



I am very sorry but this is not correct don't consider it please, I am too a learner...... SORRY!

Answer 2

2x+y=9- - - - - (I)

and

4x-y=15- - - - - (ii)

from (I)

2x+y=9

y=9-2x- - - - -(iii)

substitute the value of y in (ii)

4x-y=15

4x-(9-2x)=15

4x-9+2x=15

6x=15+9

6x=24

x=24/6

x= 3

now , substitute the value of x in equation (iii)

y=9-2x

y=9-6

y=3

therefore x=3 and y=3

hope this helps

mark it as best plz