Question

3x-5y=4,9x-2y = 7 solve by subtitution and elimination

Answer 1

hope it will help you....:-)

Answer 2

Answer:

x = 27/26, y = -5/13

Step-by-step explanation:

Substitution method:

Given pair of equations,

3x-5y = 4

=> 3x = 4+5y ----(1)

and

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

Substitute equation (1) in equation (2), we get

=> 3(4+5y)-2y = 7

=> 12+15y-2y = 7

=> 13y = 7 - 12

=> 13y = -5

=> y = -5/13

Put y value in equation (1),we get

$3x = 4+5\times \left(\frac{-5}{13}\right)$

$\implies 3x = 4-\frac{25}{13}$

$\implies 3x = \frac{52-25}{13}$

$\implies x = \frac{27}{26}$

Elimination method:

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

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

/* multiply equation (1) by 3 , and subtract from equation (2), we get

9x-2y = 7

9x-15y = 12

_______________

0 + 13y = -5

_______________

y = -5/13

/* Substitute y = -5/13 in equation (1) , we get

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

=> 3x +25/13 = 4

=> 3x = 4-(25/13)

=> 3x = (52-25)/13

=> x = 27/26

Therefore,.

x = 27/26, y = -5/13

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