Question

If 3x+5y =9 and 5x+3y =7 then what is the value of x+y?
A) 2
B) 16
C) 9
D) 7​

Answer 1

$3x + 5y = 9 and 5x + 3y = 7$

By doing substitution method

$3x=9–5y$

$X=(9–5y)/3$

Putting this value in equation 2 then we get

$5(9–5y)/3+3y=7$

$45-25y+9y=21$

$45–21=25y-9y</strong></p><p></p><p><strong>[tex]45–21=25y-9y24=16y</strong></p><p></p><p><strong>[tex]45–21=25y-9y24=16y$

$Y=24/16$

Putting value of y in equation 1 then we

$3x+5*24/16=9$

$3x=9–15/2$

$3x=(18–15)2$

$X=1/2$

So our answer is

$X=1/2and y=24/16 =3/2 \\ \\ \\ \\ </strong></p><p></p><p><strong>[tex]X=1/2and y=24/16 =3/2 \\ \\ \\ \\ Then 1/2+3/2</strong></p><p></p><p><strong>[tex]X=1/2and y=24/16 =3/2 \\ \\ \\ \\ Then 1/2+3/2$

Taking l. C. M both side

$L. C. M. =2$

$Then</strong></p><p></p><p><strong>[tex]Then4/2</strong></p><p></p><p></p><p></p><p><strong>[tex]Then4/2$

2. is Answer