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help pls!The partial solution to a system of equations below contains an error. Find and correct the mistake to find the correct value of y. 2x + 2y = 4 x + 4y = 14 Steps1. X=- 4y + 14 2. 2(-4y +14) = 4 3. - 8y + 28 = 4. - 8y = - 24 5. y =-3

User Luizgrs
by
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1 Answer

5 votes

Answer

The error occured from step 2.

After correcting the error and solving,

x = -2

y = 4

Step-by-step explanation

The system of equations

2x + 2y = 4 ........ equation 1

x + 4y = 14 ........ equation 2

The solution in steps, using the substitution method as presented in the question will be checked one at a time to find the error

Step 1)

x = -4y + 14

Here x is made the subject of formula from equation 2.

Step 2)

2 (-4y +14) = 4

Here, the expression obtained for x in step 1 is substituted for x in eqn 1.

2x + 2y = 4

2 (-4y + 14) + 2y = 4

This is where the first error comes into play. The + 2y after substituting for x has been ignored here. This changes everything now.

Step 3)

- 8y + 28 = 4

After correcting the mistake in step 2, it should lead us to

2 (-4y + 14) + 2y = 4

-8y + 28 + 2y = 4

-6y + 28 = 4

Step 4)

- 8y = - 24

Following from correcting that error, if we subtract 28 from both sides, we will have

-6y + 28 = 4

-6y + 28 - 28 = 4 - 28

-6y = -24

Step 5)

y = -3​

Further correcting the error will lead us to divide both sides by -6

-6y = -24

(-6y/-6) = (-24/-6)

y = 4

If y = 4, recall that x = -4y + 14

x = -4 (4) + 14

x = -16 + 14

x = -2

Hope this Helps!!!!

User Jesse Jashinsky
by
8.1k points
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