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(a – b)x + (a + b)y = a^2 – 2ab – b^2, (a + b)(x + y) = a^2 + b^2 gives the following solution: - Mathematics

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Question

(a – b)x + (a + b)y = a2 – 2ab – b2, (a + b)(x + y) = a2 + b2 gives the following solution:

Options

  • `x = a + b, y = (-2ab)/(a + b)`

  • `x = (-2ab)/(a + b), y = a + b`

  • `x = a + b, y = (2ab)/(a + b)`

  • `x = (2ab)/(a + b), y = a + b`

MCQ
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Solution

`bb(x = a + b, y = (-2ab)/(a + b))`

Explanation:

Step 1: Simplify Equations

The given system of equations is:
  1. (a – b)x + (a + b)y = a2 – 2ab – b2
  2. (a + b)(x + y) = a2 + b2

Expand the second equation:

(a + b)x + (a + b)y = a2 + b2

Step 2: Eliminate the y Variable

Subtract the first equation from the simplified second equation to eliminate the y term:

[(a + b)x + (a + b)y] – [(a – b)x + (a + b)y]

= [a2 + b2] – [a2 – 2ab b2]

Simplify the expression:

(a + b – (a – b))x = a2 + b2 – a2 + 2ab + b2

(a + b – a + b)x = 2ab + 2b2

(2b)x = 2b(a + b)

Step 3: Solve for x

Assuming b ≠ 0, divide both sides by 2b:

`x = (2b(a + b))/(2b)`

x = a + b

Step 4: Solve for y

Substitute the value of x into the simplified second equation:

(a + b)x + (a + b)y = a2 + b2

(a + b)(a + b) + (a + b)y = a2 + b2

(a + b)2 + (a + b)y = a2 + b2

a2 + 2ab + b2 + (a + b)y = a2 + b2

Subtract a2 + b2 from both sides:

2ab + (a + b)y = 0

(a + b)y = –2ab

Assuming a + b ≠ 0, divide both sides by (a + b):

`y = (-2ab)/(a + b)`

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Chapter 5: Simultaneous Linear Equations - Exercise 5F [Page 123]

APPEARS IN

Nootan Mathematics [English] Class 9 ICSE
Chapter 5 Simultaneous Linear Equations
Exercise 5F | Q 10. | Page 123
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