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

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

Sum

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

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Chapter 6: Simultaneous (Linear) Equations [Including Problems] - Exercise 6 (A) [Page 79]

Chapter 6 Simultaneous (Linear) Equations [Including Problems]
Exercise 6 (A) | Q 7 | Page 79

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