Question

By substitution method find 9x-4y=2000 and 7x-3y=2000

Answer 1

Answer :

Given,

9x - 4y = 2000 ...(i)
7x - 3y = 2000 ...(ii)

From (i), we get

9x = 2000 + 4y

⇒ x = (2000 + 4y)/9

Now, substituting x = (2000 + 4y)/9 in (ii), we get

7 × (2000 + 4y)/9 - 3y = 2000

⇒ (14000 + 28y)/9 - 3y = 2000

⇒ (14000 + 28y - 27y)/9 = 2000

⇒ 14000 + y = 18000

⇒ y = 18000 - 14000

⇒ y = 4000

Now,

x = (2000 + 4 × 4000)/9

= (2000 + 16000)/9

= 18000/9

= 2000

Therefore, the required solution is

x = 2000, y = 4000

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Answer 2

Answer:

it is done by using substitution, elimination aur cross multiplication method