Question

if 4x+5y=11 and 5x+4y=7, then what is the value of x+y​

Answer 1

Your Ans is x + y = 2 .

For Solution , refer the attachment !✨

Answer 2

$\Large{\underbrace{\sf{\purple{Required\:Answer:}}}}$

$\underline{\underline{\huge{\blue{\tt{\textbf Given :-}}}}}$

• 4x+5y=11 and 5x+4y=7 is given equation

$\underline{\underline{\huge{\red{\tt{\textbf Find :-}}}}}$

• value of x+y= ???

$\underline{\underline{\huge{\blue{\tt{\textbf Solution :-}}}}}$

4x+5y=11 ______________(❶)

5x+4y=7 ______________(❷)

Using elimination method:-

Multiple eq ❶ by 5 and ❷ by 4:-

We have,

4x+5y=11 ______________(❶) X 5

5x+4y=7 ______________(❷) X 4

_____________

after multiplying both side we get:-

20x+ 25y= 55______________(❸)

20x+ 16y= 28______________(❹)

________________

on substracting equation ❸ and❹ we get:-

⟼9y= 27

⟼y= 27/9

⟼y = 3

Now,

Put value of y in equation ❶

↬4x+5y=11

↬4x + 5(3)= 11

↬4x+ 15= 11

↬4x = 11-15

↬4x = -4

$x = \frac{ - 4}{ \: 4} \: = - 1 \\ x = - 1$

we have to find :-

• x+y

so

↬ x= -1 and 3

x+y= - (1) + 3 =2

↬ therefore (x+y)= 2 ..ans.

___________