Question

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

Answer 1

$\sf\huge {\underline{\underline{{Solution}}}}$

=> x+2y = 5

=> 2x+y= 7

We can solve the above equation in various ways we here solve by elimination and substitution method:

Solving through elimination method

=>x+2y= 5------× 2

=>2x+y=7-------×1

New Equation obtained

=> 2x+4y=10

=> 2x+y=7

=>$(-)(-)\:(-)$

____________

4y-y= 10-7

3y= 3

y= 1

Put y's value in this Equation

=>x+2y= 5

=>x+2=5

=> x= 3

x=3

Finding value of x+y= 3+1=4

hence, x+y is 4

Alternative Method:

Solving through substitution method:

=> x+2y= 5

x= 5-2y-----(1)

From equation 1

=> 2x+y=7

=> 2(5-2y)+y=7

=> 10-4y+y=7

=> 10-3y=7

=>-3y= 7-10

=> -3y= -3

y=1

X= 5-2y

x= 5-2=3

X= 3

Answer 2

Answer:

x+y= 4

Step-by-step explanation:

x+2y=5 and 2x+y=7

By using substitution method

2(x+2y)=2(5)

2x+y=7

Therefore;

2x+4y=10

2x+ y. =7

_________

0+3y=3

_________

3y=3

y=1

hence

using y value in above any statement

we get x=3(2x+4y=10)

therefore

x+y=3+1

x+y=4

hope this will help you