Question

2x-3y=7;5x+y=9
In substitution method

Answer 1

Answer:

x=2

y=-1

Step-by-step explanation:

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

5x+y=9=>(2)

(1)=>      2x-3y=7

(2)*3=> 15x+3y=27

          __________

           17x=34

x=2

In (1)=>2(2)-3y=7

           -3y=7-4

           -3y=3

y=-1

Answer 2

Solution:

Given Equation:

=> 2x - 3y = 7

=> 5x + y = 9

By Substitution Method:

=> 2x - 3y = 7       .............(1)

=> 5x + y = 9        .............(2)

=> y = 9 - 5x

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

=> 2x - 3y = 7

=> 2x - 3(9 - 5x) = 7

=> 2x - 27 + 15x = 7

=> -27 + 17x = 7

=> 17x = 7 + 27

=> 17x = 34

=> x = 34/17

=> x = 2

Put value of x in Equation 2, we get

=> 5x + y = 9

=> 5(2) + y = 9

=> 10 + y = 9

=> y = 9 - 10

=> y = -1

So, x = 2 and y = -1

____________________________________________________________________________________________________

Now, By using Eliminating Method:

=> 2x - 3y = 7       .............(1)

=> 5x + y = 9        .............(2)

Multiply Equation (2) by (-3), we get

=> -15x - 3y = -27     ............(3)

Now, subtract Equation (3) by Equation (2), we get

2x - 3y = 7

-15x -3y = -27

__________

=> x = 2

Put value of x in Equation 2, we get

=> 5x + y = 9

=> 5(2) + y = 9

=> 10 + y = 9

=> y = 9 - 10

=> y = -1

So, x = 2 and y = -1