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X + 4y = 2
-x + y = 8

User Rosey
by
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1 Answer

3 votes

Answer:

y = 2

x = -6

Step-by-step explanation:

Looking at the two equations, we notice right away that we can re-arrange the first equation to solve for x.

x + 4y = 2 becomes x = 2 - 4y

Now, we see that the second equation has an x in it. We replace the x in the second equation with the value of x we just found (using the first equation).

-x + y = 8 becomes -(2 - 4y) + y = 8

Simplify the left side!

1. Distribute the negative

-2 +4y + y = 8

2. Simplify like terms

-2 + 5y = 8

3. Move the -2 to the right side (changing its sign as we do so)

5y = 8 + 2

5y = 10

4. Divide both sides by 5

y = 2

NOW TO FIND X

Since we have the value for y, we can plug it in an equation to find x. We will use the second equation.

-x + y = 8 becomes -x +2 = 8

1. Move the 2 to the right side:

-x = 8 - 2

-x = 6

2. Divide both sides by -1:

x = -6

Now we come to a very important step: we must check our answers. First, we will plug in our numbers for x and y into the first equation.

x + 4y = 2

(-6) + 4(2) = 2

-6 + 8 = 2

2 = 2

The variables hold true for that equation. Now we check them with the second equation!

-x + y = 8

-(-6) + 2 = 8

6 + 2 = 8

8 = 8

Both our answers are right!

Hope this helped!!!

User Alexmurray
by
8.5k points

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