Consider the system of equations {3x+4y=2

{2x-4y=8

Which is its solution?

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2

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)

Explanation:

The quickest way is to use elimination

3

x

+

4

y

=

2

+

2

x

-

4

y

=

8

-

-

-

-

-

5

x

=

10

⇒

x

=

2

Now substitute into one of the original eqns.

3

*

2

+

4

y

=

2

6

+

4

y

=

2

4

y

=

-

4

⇒

y

=

-

1

check in other eqn.

2

x

-

4

y

=

8

2

*

2

-

(

4

*

-

1

)

=

4

-

-

4

=

4

+

4

=

8

√

solns

(

2

,

-

1

)

This is the solution to your promblem

(

2

,

-

1