Question

3x+ 5y= 20. x+y= 7. solve by substituting method​

Answer 1

Step-by-step explanation:

x+y=7

x=7-y

substituting in 3x+5y=20

3×(7-y)+5y=20

21-3y+5y=20

2y=1

y=1/2

Answer 2

3x+5y=20------×1_____1

x+y=7-------×3_______2

EQUATING IN 1 AND 2 after,we get:-

3x+5y=20

3x+3y=21

2y=-1

y=-1/2

SUBSTITUTING the value of y,we get--

x+1/2=7

x=7(-1/2)

x=(14-1)/2

HENCE, x=6.5 and y=-0.5

OR, x=13/2 and y=-1/2