Question

If x+2y=5 and 2x+y=7 then find the value of x+y​

Answer 1

Given Equation

➝x + 2y = 5 (i)

➝2x + y = 7 (ii)

To Find

➝x + y

Now Take

➝x + 2y = 5 (i)

➝2x + y = 7 (ii)

Apply Substitution Method

We can write (i)eq as

➝x + 2y = 5 (i)

➝x = 5 - 2y (iii)

Put the value of x on (ii)eq

➝2x + y = 7

➝2(5 - 2y) + y = 7

➝10 - 4y + y = 7

➝-3y = 7 - 10

➝-3y = -3

➝y = 3/3

➝y = 1

Now Put the value of y on (iii) eq

➝x = 5 - 2y

➝x = 5 - 2(1)

➝x = 5 - 2

➝x = 3

We get

➝x = 3 and y = 1

We have to find x + y

➝x + y

➝3 + 1

➝4

Answer is 4

Answer 2

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• x+2y = 5 - - - - - - - (i)
• 2x+y = 7 - - - - - - - (ii)

First equation :-

x + 2y = 5

Second equation :-

2x + y = 7

Put x in equation

2(5-2y) + y = 7

10-4y +y = 7

10-3y = 7

3y = 7-10

3y = -3

y = -3/3

= 1

Put y in equation

x = 5-2y

x = 5-2

x = 3

Value - x = 3 & y = 1

➖➖➖➖➖➖➖➖

x + y

= 3+1

= 4

______________________

hope it helps