Question

If 2x + 4y = 5 and 4x + 2y =7, then what is the value of x + y? *​

Answer 1

Answer :-

Method I :-

→ 2x + 4y = 5 -i

→ 4x + 2y = 7 -ii

Adding both the equations :-

→ 2x + 4y + 4x + 2y = 7 + 5

→ 2x + 4x + 4y + 2y = 12

→ 6x + 6y = 12

→ 6 ( x + y ) = 12

→ x + y = 12 / 6

→ x + y = 2

Method II :-

→ 2x + 4y = 5 -i

→ 4x + 2y = 7 -ii

Multiplying equation i by 2 :-

→ 2 ( 2x + 4y = 5 )

→ 4x + 8y = 10 -iii

Subtracting equation i by iii :-

→ 4x + 8y - 4x - 2y = 10 - 7

→ 6y = 3

→ y = ½

Substituting the value in equation i :-

→ 2x + 4y = 5

→ 2x + 4 × ½ = 5

→ 2x + 2 = 5

→ 2x = 3

→ x = 3 / 2

x + y = 3 / 2 + 1 / 2 = 4 / 2 = 2

Value of x + y = 2