Question

$2x + 1 \div {y }^{2} - 4y + 9$
​

Answer 1

Answer:

(

1

6

,

−

7

3

)

Explanation:

Labelling the equations.

2

x

+

4

y

=

−

9

→

(

1

)

2

x

+

y

=

−

2

→

(

2

)

Notice that the term

2

x

is common to both equations.

Thus, subtracting (2) from (1) will eliminate it leaving an equation in y which we can solve.

Subtract

(

1

)

−

(

2

)

term by term

(

2

x

−

2

x

)

+

(

4

y

−

y

)

=

(

−

9

−

(

−

2

)

)

⇒

3

y

=

−

7

divide both sides by 3

3

y

3

=

−

7

3

⇒

y

=

−

7

3

Substitute this value into either (1) or (2) and solve for x

Substituting in ( 2)

2

x

−

7

3

=

−

2

⇒

2

x

=

−

2

+

7

3

=

1

3

dividing both sides by 2

2

x

2

=

1

3

2

⇒

x

=

1

3

×

1

2

=

1

6

⇒

(

1

6

,

−

7

3

)

is the solution

graph{(y+2x+2)(y+1/2x+9/4)=0 [-12.66, 12.65, -6.33, 6.33]}