Question

4x - 3y = 15 and 3x+2y =7 Solve by using substitution method.​

Answer 1

Step-by-step explanation:

3x+2y=7 ----- (1)

4x−3y=−2----- (2)

Multiply equation (1) by 3 and equation (2) by 2, then subtract

9x+6y=21

8x−6y=−4

______________

17x=17

x=

17

17

=1

Put the value of x in equation (1), we get

3x+2y=7

3(1)+2y=7

2y=73

2y=4

y=

2

4

=2

Therefore the solution is (1, 2)

Answer 2

Answer:

{X,Y}= (3, -1)

Step-by-step explanation:

Solve equation [2] for the variable  x  

 

 [2]    4x = 3y + 15

 [2]    x = 3y/4 + 15/4

Plug this in for variable  x  in equation [1]

  [1]    3•(3y/4+15/4) + 2y = 7

  [1]    17y/4 = -17/4

  [1]    17y = -17

Solve equation [1] for the variable  y  

  [1]    17y = - 17  

  [1]    y = - 1  

By now we know this much :

   x = 3y/4+15/4

   y = -1

Use the  y  value to solve for  x  

   x = (3/4)(-1)+15/4 = 3