Mathematics
Domsemien328
44

1. What is the value of r in the equation 4r – 8 = 5r + 12? (4 points) –20 –1 1 20 2. 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 3. What is the value of n in the equation 3n + 2(n + 2) = 9n + 12? (4 points) –4 –2 2 4 4. How many solutions can be found for the equation –4x – 11 = 2(x – 3x) + 13? (4 points) None One Two Infinitely many 5. 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

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(2) Answers
enigma

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

joqual

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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