145k views
1 vote
What is the solution to the system of equations?

2x + y = -3
x - 2y = -4

( __ , __ )

User Blue Ice
by
8.4k points

2 Answers

4 votes

Answer: x=-2 y=13

2(-2)+1=-3 check

-2-2=-4 check

Explanation:

Horner's method:

2 1 -3

1 -2 -4

delta = det(

2 1

1 -2) = 2×-2 - 1 = -5

x = det(

-3 1

-4 -2)/-5 = (-2×-3-1×-4)/-5 = -2

y = det(

2 -3

1 -4)/-5 = (-8+3)/-5 = 1


Or by elimination

x = 2y - 4 from adding 2y=2y to second eqn

2(2y-4)+y=-3 by substituting for x in first.

4y-8+y=-3

5y=8-3=5

y=1

x=2y-4=2-4=-2



User OFca
by
7.0k points
0 votes

Answer:

(-2,1)

Explanation:

2x + y = -3

x - 2y = -4


Multiply the first equation by 2 so we can eliminate y

2(2x + y = -3 )

4x +2y = -6

Add the second equation

4x +2y = -6

x - 2y = -4

-------------------

5x = -10

Divide by 5

5x/5 = -10/5

x = -2

We still need to find y

2x + y = -3

Substitute x in

2(-2) +y = -3

-4 +y = -3

Add 4 to each side

-4+4 +y = -3+4

y = 1

User SquiresSquire
by
8.2k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories