MATH 125 LA Valley College Authentic Assessment Error Analysis Exercises

RUBRIC:

GRADE(10points)-3pointswillbegivenforfindingerror,2 points for a logical explanation on why it is incorrect.After posting your response, 5 points will be giving for replying to 3 of your classmates post.

AUTHENTIC ASSESSMENT: ERROR ANALYSIS

Find the errors, if any, in the following problems; explain why it is incorrect:

1. Find the GCF for 108x3y2 and 56x2y4.

108 = 2*54 = 2*2*27 =

2*2*3*9 = 2*2*3*3*3 = 22*33so 108x3y2 = 22*33 x3 y2

56 = 2*28 = 2*2*14 =

2*2*2*7 = 23 * 7

so 56x2y4 = 23 * 7 x2 y4

The GCF = 23 * 33 * 7 x3 * y4 = 504 x3 * y4

2. Multiply: (2x – 5) (3×2 – 4x + 1) =

6×3 – 8×2 + 2x – 15×2 – 20x – 5 =

6×3 – 23×2 – 18x – 5

3. Factor: 16×2 – y2 = (4x – y)2

4. Factor: 8ax – 4a – 6x + 3 =

4a(2x – 1) + 3(2x – 1) =

(4a + 3)(2x – 1)