Question

3 X + 5 Y is equals to 9 and 5 x + 3 Y is equals to 7 then find the value of x + Y please answer if you know and in full format

Answer 1

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

Multiply eq1 by 5 and eq2 by 3 and subtract eq2 from eq1

15x + 25y = 45
-15x - 9y = -21

16y = 24

y = 24/16 = 3/2

Put y in eq1


3x + 5×3/2 = 9

3x = 9 - 15/2

3x = 3/2

x = 1/2

Now, x + y = 3/2 + 1/2

= 4/2 = 2


x + y = 2


Thanks

Answer 2

3x+5y=9 …(1)

5x+3y=7 …(2)

Let us simplify the equations by eliminating a variable

Make the coefficients of X or Y equal

Multiply equation (1) with 5 and equation (2) with 3

We get 15x+25y=45 and 15x+9y=21

Now subtract the equations, we get

(15x+25y)-(15x+9y)=(45–21)

16y=24, y= 24/16 = 3/2

Substituting the value of y in equation (1) we get

3x+5(3/2)=9

3x+15/2=9

3x=9–15/2

3x=3/2

x =1/2

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

x+y=2

The other method is simply add equations (1) & (2)

You get

8x+8y=16

x+y=2

Answered By SUDIN