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What is the value of r in the equation 4r – 8 = 5r + 12? (4 points)



–20



–1



1



20









Which of these is a simplified form of the equation 8y + 4 = 6 + 2y + 1y? (4 points)



5y = 2



5y = 10



11y = 2



11y = 10









What is the value of n in the equation 3n + 2(n + 2) = 9n + 12? (4 points)



–4



–2



2



4









How many solutions can be found for the equation –4x – 11 = 2(x – 3x) + 13? (4 points)



None



One



Two



Infinitely many









The work of a student trying to solve the equation 2(2x – 3) = 6 + 2x + 4 is shown below:


Step 1: 2(2x – 3) = 6 + 2x + 4


Step 2: 4x – 3 = 10 + 2x


Step 3: 4x – 2x = 10 + 3


Step 4: 2x = 13


Step 5: x = 6.5


In which step did the student first make an error and what is the correct step? (4 points)



Step 2: 4x – 6 = 10 + 2x



Step 2: 4x – 3 = 2 + 2x



Step 3: 4x + 2x = 10 + 3



Step 3: 4x – 2x = 10 - 3

Verified Answer :

learnablelearner
  1. 4r-8=5r+12
    4r-5r=12+8
    -r=20(divide by -1)
    r=-20

    2. 8y+4=6+2y+1y
    8y+4=6+3y
    8y-3y=6-4
    5y=2

    3. 3n+2(n+2)=9n+12
     3n+2n+4=9n+12
    5n+4=9n+12
    5n-9n=12-4
    -4n=8(divide by -4)
    n=-2

    4. -4x-11=2(x-3x)+13
    -4x-11=2x-6x+13
    -4x-11=-4x+13
    -4x+4x=13+11
    ∴there is no answer. it is undefined.

    5.2(2x-3)=6+2x+4
    4x-6=10+2x
    4x-2x=10+6
    2x=16
    x=8
amelia18
  1. 20
    Add -8 to both sides . Then add -5r .
    R=20
    2.5y=2
    3. 2
    4 .there's only one solution but that solution can be expressed differently.
    0.66666 , 2/3
    5.there are different errors , step 3 shows addiction then it shows subtraction , there is also a mistake (step2).

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