# Solve the following pair of linear equations: 3x − 5y = 4 2y + 7 = 9x - Mathematics

Sum

Solve the following pair of linear equations:

3x − 5y = 4
2y + 7 = 9x

#### Solution

Given,

3x − 5y = 4  ...........(i)
2y + 7 = 9x  .............(ii)
From (ii), x =(2"y" +7)/9  ...............(iii)

substitute x = (2"y" +7)/9 in (i), then

3((2"y"+7)/9)-5"y" =4

⇒ (2"y"+7)/3 - 5"y" = 4

⇒ (2"y"+7-15"y")/3 = 4

⇒ 7 - 13y = 12

⇒ "y" = - 5/13

Put "y" = - 5/13 in (iii), then

"x" = (2(-5/13)+7)/9 = (-10+91)/(9xx13)

⇒ x = 9/13

Hence, x = 9/13 and y=-5/13 is the solution for the given pair of linear equations.

Concept: Pair of Linear Equations in Two Variables
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