Question

Solve the system using elimination. Write the solution as an ordered pair. (1 point) SHOW YOUR WORK FOR FULL CREDIT! (2 points)

5x + 4y = 1
-3x + 4y = -7

Answer 1

inal answer is x=1 and y=-1.

Explanation:

Given equations are:

5x+4y=1 ...(i)

and

-3x+4y=-7 ...(ii)

Now we need to solve this by elimination method.

Subtract equation (ii) from (i)

5x+4y -(-3x+4y) =1 -(-7)

5x+4y +3x-4y =1+7

8x =8

`x=(8)/(8)`

x=1

Now plug x=1 into equation (i)

5x+4y=1

5(1)+4y=1

5+4y=1

4y=1-5

4y=-4

`y=(-4)/(4)`

y=-1

Hence final answer is x=1 and y=-1.

Answer 2

Answer: (1,-1)

Explanation:

- You can multiply the first equation by -1

- Add the equations.

- Solve for x, as following:

`\left \{ {{-5x - 4y = -1} \atop {-3x + 4y = -7}} \right.\\------\\-8x=-8\\x=1`

- Substitute the value of x into any of the original equations and then you must solve for y:

`5(1)+4(y)=1\\4y=-4\\y=-1`

Therefore, the solution is: (1,-1)