Question

Solve this pair of linear equation using substitution method: x+y=7 and 3x-2y=11.

Answer 1

Answer:

y=4,x=3

Step-by-step explanation:

firstly no. the equation as 1 and 2

x+y=7____1

3x-2y=11_____2

now by equation 1 , we get

x=7-y

no. the equation 3

by putting the value of x in equation 2,we get

3(7-y)-2y=11

,now multiply 7-y by 3

21-3y-2y=11

21-5y=11

-5y=11-21

-5y=-20

cut the subtraction symbol of both side

5y=20

y=20/5

y=4

now put the value of y in equation 1

x+4=7

x=7-4

x=3

Answer 2

Answer:

x= -4

y=11

Step-by-step explanation:

by using substitution method

x+y=7-----(1)eq.

x+y=7-----(1)eq.3x-2y=11------(2)eq.

x+y=7-----(1)eq.3x-2y=11------(2)eq.from eq. (1)

x+y=7

x+y=7x=7-y-----(3)

putting the value in eq. (2)

3x-2y=11

3x-2y=113(7-y)-2y=11

3x-2y=113(7-y)-2y=1121-3y-2y=11

3x-2y=113(7-y)-2y=1121-3y-2y=11-1y=11-21

3x-2y=113(7-y)-2y=1121-3y-2y=11-1y=11-21-1y= -11

y=11

put the value in eq.(3)

x=7-y

x=7-yx=7-11

x=-4