Question

2x-y=1, 5x+2y=25 do in substitution method​

Answer 1

Answer:

y=2x-1 put in eq (2)

5x+ 2(2x-1)=25

9x=27

x=3

X=3 put in any equation

then y=5

Answer 2

2x-y=1, 5x+2y=25

On comparing the above equation in the standard form

a1=2 ,b1=-1 ,c1=-1

a2=5 ,b2=2 ,c1=-25

Here we see that a1/a2 is not equal to b1/b2

So, by substitution method

2x-y=1........(I)

5x+2y=25........(II)

2x=1+y

x=1+y/2

put the value of x=1+y/2 in eq. in (II)

5(1+y/2)+2y=25

5+5y/2+2y=25

5y/2 +2y=25-5

5y+4y=20*2

9y=40

y=40/9