Question

Solve the following pair of linear equation by elimination method
1) 3x - 5y - 4 = 0
9x = 2y + 7
2) x/2 + 2y/3 = -1
x - y/3 = 3

Answer 1

Hi ☺

here is your answer:-

==================================

given,

3x - 5y - 4 = 0

9x = 2y + 7

now,

3x - 5y - 4 = 0--------(1)

9x = 2y + 7

=> 9x - 2y - 7 = 0 -----------(2)

(1) × 3 => 9x - 15y - 12 = 0 --------(3)

(2) × 1 => 9x - 2y - 7 = 0 ----------(4)

_____________________________

(3) - (4) => - 13y - 5 = 0

=> - 13y - 5 = 0

=> - 13y = 5

=> y = -5/13

value of y put in (1)

3x - 5 ( - 5/13 ) - 4 = 0

=> 3x + 25/13 - 4 = 0

=> 3x = 4 - 25/13

=> 3x = 52 - 25/13

=> 3x = 27/13

=> x = 27/13 × 1/3

=> x = 9/13

.°. x = 9/13 , y = - 5/13☺

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2)

x/2 + 2y/3 = - 1

=> 3x + 4y/6 = - 1

=> 3x + 4y = - 6-------------(1)

x - y/3 = 3

=> 3x - y/3 = 3

=> 3x - y = 9 ----------(2)

(1) - (2) => 3x + 4y = - 6

3x - y = 9

____________________________

5y = - 15

=> y = - 3

now value of y put in ( 1)

3x + 4 ( - 3 ) = - 6

=> 3x - 12 = - 6

=> 3x = - 6 + 12

=> 3x = 6

=> x = 6/3 = 2

.°. x = 2, y = - 3☺

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Answer 2

Brainly User

Hi ☺

here is your answer:-

==================================

given,

3x - 5y - 4 = 0

9x = 2y + 7

now,

3x - 5y - 4 = 0--------(1)

9x = 2y + 7

=> 9x - 2y - 7 = 0 -----------(2)

(1) × 3 => 9x - 15y - 12 = 0 --------(3)

(2) × 1 => 9x - 2y - 7 = 0 ----------(4)

_____________________________

(3) - (4) => - 13y - 5 = 0

=> - 13y - 5 = 0

=> - 13y = 5

=> y = -5/13

value of y put in (1)

3x - 5 ( - 5/13 ) - 4 = 0

=> 3x + 25/13 - 4 = 0

=> 3x = 4 - 25/13

=> 3x = 52 - 25/13

=> 3x = 27/13

=> x = 27/13 × 1/3

=> x = 9/13

.°. x = 9/13 , y = - 5/13☺

===================================

2)

x/2 + 2y/3 = - 1

=> 3x + 4y/6 = - 1

=> 3x + 4y = - 6-------------(1)

x - y/3 = 3

=> 3x - y/3 = 3

=> 3x - y = 9 ----------(2)

(1) - (2) => 3x + 4y = - 6

3x - y = 9

____________________________

5y = - 15

=> y = - 3

now value of y put in ( 1)

3x + 4 ( - 3 ) = - 6

=> 3x - 12 = - 6

=> 3x = - 6 + 12

=> 3x = 6

=> x = 6/3 = 2

.°. x = 2, y = - 3☺

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