Question

solve system of equations using substitution 2x-3y=7, y=3x-7​

Answer 1

☞ANSWER:-

Given Equations:-

2x-3y=7

y = 3x -7

☞How to Solve:-

First we will SOLVE any one of the equations

then find any one value let us say of x or y

Then find value

And then find the second value.

In this, we are already given the value of y.

Placing directly we get,

2x -3(3x-7)=7

2x -9x + 21 = 7

- 7x = - 14

x = 2.

Now, y

y = 3×2-7

y = -1 is the answer.

✷Things to Note:-

• Always in substitution find the value of one with respect to the other
• Applicable only in two variable question
• Remember to find the second value
• This can be brought out only by placing the value of first one.

Answer 2

Explanation:

Given -

• 2x - 3y = 7
• y = 3x - 7

To Find -

• Value of x and y

By substitution method :-

⇝y = 3x - 7

Now,

Substituting the value of y on 2x - 3y = 7, we get :-

⇝2x - 3(3x - 7) = 7

⇝2x - 9x + 21 = 7

⇝-7x = -14

⇝x = 2

Now,

Substituting the value of x on y = 3x - 7, we get :-

⇝y = 3(2) - 7

⇝y = 6 - 7

⇝y = -1

Hence,

The value of y is -1 and x is 2.

Verification :-

• 2x - 3y = 7

⇝2(2) - 3(-1) = 7

⇝4 + 3 = 7

⇝7 = 7

LHS = RHS

And

• y = 3x - 7

⇝-1 = 3(2) - 7

⇝-1 = 6 - 7

⇝-1 = -1

LHS = RHS

Hence,

Verified...

It shows that our answer is absolutely correct.