Question

solve the equation by substitution method..
1. 3x-y = 3
9x - 3y = 9

2. 0.5x + 0.8y = 3.4
0.6x - 0.3y = 0.3

Answer 1

there is no need to solve it

2: solved see in pic

Answer 2

1.



3x-y=3 -----(1)

9x-3y=9------(2)

x= 3+y / 3 

9 ( 3+y / 3) = 9 

27+9y /3 = 9

27 +9y = 9*3

9y = 27-27

9y =0

y=0/9 

y=0

(put value of y in 1st equation)

3x-y=3

3x-0=3

3x=3

x=3/3

x = 1

(1,0)

therefore, value of x and y by substitution method is 1 and 0