Question

3x+4y=12 and 7x+5y=2 solve linear equation by substitution method​

Answer 1

Answer:

3x+4y=12

that means 3x=12-4y

x=(12-4y) / 3

Substitute value of x in 2nd eq. i.e 7x+5y=2

7{(12-4y) / 3 } + 5y = 2

(84-28y ) /3 +5y=2

84-28y+15y=6 by taking LCM

84-13y=6

13y= 84-6=78

y=78/13

y=6

put value of y in eq. 1

x= (12-24) /3 = -12/3 = -4

it means x= -4 , y = 6