Question

3x + 5y = 21 ; -7x -6y = -49 by using elimination method

Answer 1

x = 7 and y = 0

Given:

3x + 5y = 21

-7x - 6y = -49

To find:

x and y using the elimination method

Solution:
The elimination method is a method of solving a set of linear equations.

In this method, the coefficients of one variable are made equal and then the equations are compared to derive an equation with one variable.

The given equations are

3x + 5y = 21 ...(i)

-7x - 6y = -49 ...(ii)

Multiplying equation (i) with 7, we get:

21x + 35y = 147...(iii)

Multiplying equation (ii) with 3, we get:

-21x - 18y = -147 ...(iv)

Adding equations (iii) and (iv), we get:

21x + 35y - 21x -18y = 147 - 147

=> 35y - 18y = 0

=> y = 0

Putting the value of y in equation (i),

3x + 0 = 21

=> x = 21/3

=> x = 7

Hence, x = 7 and y = 0 is the solution to the given equations using the elimination method.

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Answer 2

Answer: X = 7 and Y = 0 is the solution to the given question.

Step-by-step explanation: Elimination method is used to eliminate one of the variables in the system of linear equation. This can be done by addition or subtraction in conjunction with multiplication or division.
Let us consider
3x + 5y = 21 ...... ( 1 )
-7x - 6y = -49 ..... ( 2 )
multiply equation 1 with 7 and equation 2 with 3
we get
21x + 35y = 147 ...... ( 3 )
-21x - 18y = -147 ......... ( 4 )
adding equation 3 and 4
we get
21x + 35y - 21x - 18y = 147 - 147
⇒ 35y - 18y = 0
⇒ 17y = 0
⇒ y = 0
substitute y value in equation 1
we get
3x + 5(0) = 21
⇒ 3x = 21
⇒x= 7
Hence X = 7 and Y = 0 is the solution.
The link given below provides detail explanation about elimination method.
https://brainly.in/question/54160690
Here is an example of a problem solved using elimination method in the below link
https://brainly.in/question/17187033
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