Question

((15÷x)+(16÷y)=9)+((21÷x)+(20÷y)=12)​

Answer 1

Answer:

x = 4, y = 3.

Step-by-step explanation:

Solution:

15/x + 16/y = 9 -----> Equation 1

21/x + 20/y = 12 -----> Equation 2

Assume 1/x = u and 1/y = v.

15u + 16v = 9 -----> Equation 3

21u + 20v = 12 -----> Equation 4

Multiply Equation 3 by 7 and Equation 4 by -5.

105u + 112v = 63

-105u - 100v = -60

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12v = 3

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v = 3/12 = 1/4

Subsitute v = 1/4 in equation 3.

15u + 16(1/4) = 9

15u + 4 = 9

15u = 5

u = 5/15 = 1/3

Therefore, x = 4, y = 3.