Question

5x+(4/y)=7
4x(3/y)=5
by elimination method or substitution method​

Answer 1

Answer:

x=-1 ,y= 1/3

Step-by-step explanation:

5x+4/y=7→(1) *4

4x+3/y=5→(2)*5

Then equation (1) and (2) becomes like this↓

20x+ 16/y=28 →(1)

20x+ 15/y=25 →(2)

Equation (1)-(2) gives↓

1/y=3

∴y=1/3

Then substitute the value of y in equation (1) which gives↓

20x+16*3=28

20x=28-48

∴ x= - 1

∴ The values of x = -1 and y= 1/3

Answer 2

3

and

2

:

E

q

1

:

3

(

5

x

+

2

y

)

=

7

⋅

3

E

q

2

:

2

(

4

x

−

3

y

)

=

24

⋅

2

E

q

1

:

15

x

+

6

y

=

21

E

q

2

:

8

x

−

6

y

=

48

Now I see that the

y

's will cancel if I add the two equations, so I'll do just that:

15

x

+

6

y

+

8

x

−

6

y

=

21

+

48

15

x

+

8

x

=

69

23

x

=

69

x

=

69

23

x

=

3

And then we can just plug in for

x

in one of the equations and solve for

y

:

E

q

2

:

5

⋅

3

+

2

y

=

7

15

+

2

y

=

7

2

y

=

7

−

15

2

y

=

−

8

y

=

−

4