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Solve the Pair of Linear (Simultaneous) Equation by the Method of Elimination by Substitution: 2x + 7y = 39 3x + 5y = 31

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प्रश्न

Solve the pair of linear (simultaneous) equation by the method of elimination by substitution:
2x + 7y = 39
3x + 5y = 31

योग
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उत्तर

2x + 7y = 39                           ...(1)
3x + 5y = 31                           ...(2)

2x + 7y = 39
∴ x = `[39 - 7y]/2`

Putting this value of x in (2)
`3([ 39 - 7y]/2) + 5y = 31`

`117 - 21y + 10y = 62`

`- 11y = - 55`

`y = 5`

From (1) x = `[39 - 7(5)]/2`

x = `4/2`
x = 2

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Methods of Solving Simultaneous Linear Equations by Elimination Method
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 6: Simultaneous (Linear) Equations (Including Problems) - Exercise 6 (A) [पृष्ठ ७९]

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सेलिना Concise Mathematics [English] Class 9 ICSE
अध्याय 6 Simultaneous (Linear) Equations (Including Problems)
Exercise 6 (A) | Q 7 | पृष्ठ ७९

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