For those of you who missed it... Absolute Value!!!
1. 2.  3. 4.  5. 6. Domain: (- ∞ , ∞ ) Range:  [2, ∞ ) Domain: (- ∞ , ∞ ) Range:  (- ∞, -2] Domain: (- ∞ , ∞ ) Range:  [-1, ∞ ) Domain: (- ∞ , ∞ ) Range:  [-2, ∞ ) Domain: (- ∞ , ∞ ) Range:  (- ∞, 3] Domain: (- ∞ , ∞ ) Range:  (- ∞,  1 ] Answers to Absolute Value Worksheet
Answers to Absolute Value Worksheet f(x) = 2|x - 3| + 3 f(x) = 1/3|x + 5| + 3
Answers to Absolute Value Worksheet f(x) = -3/2|x - 5| - 4 f(x) = -3/2|x + 6| - 2
Answers to Absolute Value Worksheet f(x) = 3|x - 4| - 10 f(x) = -2|x - 4| + 9
Answers to Absolute Value Worksheet f(x) = 4|x + 5| + 9 f(x) = 3/5|x + 4| - 8
2x + 3 = 6   2x + 3 = -6 2x = 3   2x = -9 x = 3/2   x = -9/2 Solving Absolute Value Equations... Absolute Value: For any real number x,  |x| = { -x, if x < 0 0, if x = 0 x, if x > 0 Recall:   When solving equations, isolate the absolute value.  Here are a few examples... 1.  5|2x + 3| =  30   |2x + 3| = 6 Don't forget to check!!! 5|6| = 30  5|-6| = 30  solution set:  {3/2, -9/2}
example 2: -2|x + 2| + 12 = 0 -2|x + 2| = -12 |x + 2| = 6 isolate the absolute value! x + 2 = -6   x = -8 x + 2 = 6   x = 4 -2|-6| + 12 = 0 -2|6| + 12 = 0 {4, -8}
5|3×+ 7|=-65 |3x + 7|=-13 absolute value cannot be  negative!! example 3: {}
{3} example 4: |2x + 12| = 7x - 3 2x + 12 = 7x - 3 2x + 15 = 7x 15  = 5x 3 = x 2x + 12 = -(7x - 3) 2x + 12 = -7x + 3 9x + 12 = 3   9x = -9   x = -1 |18| = 18 |10| = -10 reject!
Absolute Value Inequalities Recall:  |ax+b|=c, where c>0 ax+b=c  ax+b=-c |ax+b|<c  think:  between  &quot;and&quot;  -c < ax+b < c ax+b < c and ax+b > -c ax+b>c  or  ax+b<-c why? we will express < or ≤  as an equivalent conjunction using the word AND |ax+b|>c  think:  beyond  &quot;or&quot;  we will express > or ≥ as an equivalent disjunction using the word OR
I.  Less than... a)  |x| < 5 x < 5 and x >-5 written as solution set:  {x: -5< x < 5} Graph on a number line! use open circles! shade between!!! 1 0 2 3 4 5 6 7 8 9 10 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
b) |2x - 1| < 11 2x-1<11  and  2x-1>-11 2x < 12  and   2x > -10 x < 6  and   x > -5 {x: -5 < x < 6} 1 0 2 3 4 5 6 7 8 9 10 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
c) 4|2x + 3| - 11  ≤  5 4|2x + 3|  ≤  16 |2x + 3|  ≤ 4 2x + 3  ≤  4  AND  2x + 3  ≥  -4 2x  ≤  1  AND  2x  ≥  -7     x ≤  1/2  AND  x  ≥  -7/2   notice closed ends! -1 0 -2 -3 -4 -5 1 2 3 4 5
d)  |7x + 10| < 0 think.... can an absolute value be negative??? NO!! {}
II.  Greater than... a)  |x| > 5 x > 5 or x < -5 written as solution set:  {x: x > 5 or x < -5} I nterval notation (we will not use this, just set, but as an FYI):  (- ∞ , -5)  ∪  (5,  ∞ ) Graph on a number line! use open circles! shade beyond!!! 1 0 2 3 4 5 6 7 8 9 10 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
b) |2x - 1| > 11 2x-1>11  or  2x-1<-11 2x > 12  or   2x < -10 x > 6  or   x < -5 {x: x > 6 or x < -5} 1 0 2 3 4 5 6 7 8 9 10 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
c) 4|2x + 3| - 11 ≥ 5 4|2x + 3| ≥ 16 |2x + 3| ≥  4 2x + 3 ≥ 4  OR  2x + 3 ≤ -4 2x  ≥ 1  OR  2x ≤ -7    x ≥ 1/2  OR  x ≤ -7/2  notice closed ends! -1 0 -2 -3 -4 -5 1 2 3 4 5
d)  |7x + 10| > 0 think.... when is an absolute value greater than 0??? always!! {x: x  ∈   R   } x is a real number! -1 0 -2 -3 -4 -5 1 2 3 4 5
LAST ONE! 5 <  |x + 3|  ≤  7 |x + 3|  >5    |x + 3|  ≤  7 x + 3 > 5  or  x + 3 < -5 x+ 3  ≤  7  and  x + 3  ≥  -7 x > 2  or  x < -8   x  ≤  4  and  x  ≥  -10 now graph it!  graph above the number line and look for the overlap.  This is where your solution will appear. {x: -10  ≤  x < 8 or 2 < x  ≤  4} 1 0 2 3 4 5 6 7 8 9 10 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
Remember to see me, email me or ask on the wiki if you have questions!! -Ms. P

Absolute Value Notes

  • 1.
    For those ofyou who missed it... Absolute Value!!!
  • 2.
    1. 2. 3. 4. 5. 6. Domain: (- ∞ , ∞ ) Range: [2, ∞ ) Domain: (- ∞ , ∞ ) Range: (- ∞, -2] Domain: (- ∞ , ∞ ) Range: [-1, ∞ ) Domain: (- ∞ , ∞ ) Range: [-2, ∞ ) Domain: (- ∞ , ∞ ) Range: (- ∞, 3] Domain: (- ∞ , ∞ ) Range: (- ∞, 1 ] Answers to Absolute Value Worksheet
  • 3.
    Answers to AbsoluteValue Worksheet f(x) = 2|x - 3| + 3 f(x) = 1/3|x + 5| + 3
  • 4.
    Answers to AbsoluteValue Worksheet f(x) = -3/2|x - 5| - 4 f(x) = -3/2|x + 6| - 2
  • 5.
    Answers to AbsoluteValue Worksheet f(x) = 3|x - 4| - 10 f(x) = -2|x - 4| + 9
  • 6.
    Answers to AbsoluteValue Worksheet f(x) = 4|x + 5| + 9 f(x) = 3/5|x + 4| - 8
  • 7.
    2x + 3= 6 2x + 3 = -6 2x = 3 2x = -9 x = 3/2 x = -9/2 Solving Absolute Value Equations... Absolute Value: For any real number x, |x| = { -x, if x < 0 0, if x = 0 x, if x > 0 Recall: When solving equations, isolate the absolute value. Here are a few examples... 1. 5|2x + 3| = 30 |2x + 3| = 6 Don't forget to check!!! 5|6| = 30  5|-6| = 30  solution set: {3/2, -9/2}
  • 8.
    example 2: -2|x+ 2| + 12 = 0 -2|x + 2| = -12 |x + 2| = 6 isolate the absolute value! x + 2 = -6 x = -8 x + 2 = 6 x = 4 -2|-6| + 12 = 0 -2|6| + 12 = 0 {4, -8}
  • 9.
    5|3×+ 7|=-65 |3x+ 7|=-13 absolute value cannot be negative!! example 3: {}
  • 10.
    {3} example 4:|2x + 12| = 7x - 3 2x + 12 = 7x - 3 2x + 15 = 7x 15 = 5x 3 = x 2x + 12 = -(7x - 3) 2x + 12 = -7x + 3 9x + 12 = 3 9x = -9 x = -1 |18| = 18 |10| = -10 reject!
  • 11.
    Absolute Value InequalitiesRecall: |ax+b|=c, where c>0 ax+b=c ax+b=-c |ax+b|<c think: between &quot;and&quot; -c < ax+b < c ax+b < c and ax+b > -c ax+b>c or ax+b<-c why? we will express < or ≤ as an equivalent conjunction using the word AND |ax+b|>c think: beyond &quot;or&quot; we will express > or ≥ as an equivalent disjunction using the word OR
  • 12.
    I. Lessthan... a) |x| < 5 x < 5 and x >-5 written as solution set: {x: -5< x < 5} Graph on a number line! use open circles! shade between!!! 1 0 2 3 4 5 6 7 8 9 10 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
  • 13.
    b) |2x -1| < 11 2x-1<11 and 2x-1>-11 2x < 12 and 2x > -10 x < 6 and x > -5 {x: -5 < x < 6} 1 0 2 3 4 5 6 7 8 9 10 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
  • 14.
    c) 4|2x +3| - 11 ≤ 5 4|2x + 3| ≤ 16 |2x + 3| ≤ 4 2x + 3 ≤ 4 AND 2x + 3 ≥ -4 2x ≤ 1 AND 2x ≥ -7 x ≤ 1/2 AND x ≥ -7/2 notice closed ends! -1 0 -2 -3 -4 -5 1 2 3 4 5
  • 15.
    d) |7x+ 10| < 0 think.... can an absolute value be negative??? NO!! {}
  • 16.
    II. Greaterthan... a) |x| > 5 x > 5 or x < -5 written as solution set: {x: x > 5 or x < -5} I nterval notation (we will not use this, just set, but as an FYI): (- ∞ , -5) ∪ (5, ∞ ) Graph on a number line! use open circles! shade beyond!!! 1 0 2 3 4 5 6 7 8 9 10 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
  • 17.
    b) |2x -1| > 11 2x-1>11 or 2x-1<-11 2x > 12 or 2x < -10 x > 6 or x < -5 {x: x > 6 or x < -5} 1 0 2 3 4 5 6 7 8 9 10 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
  • 18.
    c) 4|2x +3| - 11 ≥ 5 4|2x + 3| ≥ 16 |2x + 3| ≥ 4 2x + 3 ≥ 4 OR 2x + 3 ≤ -4 2x ≥ 1 OR 2x ≤ -7 x ≥ 1/2 OR x ≤ -7/2 notice closed ends! -1 0 -2 -3 -4 -5 1 2 3 4 5
  • 19.
    d) |7x+ 10| > 0 think.... when is an absolute value greater than 0??? always!! {x: x ∈ R } x is a real number! -1 0 -2 -3 -4 -5 1 2 3 4 5
  • 20.
    LAST ONE! 5< |x + 3| ≤ 7 |x + 3| >5 |x + 3| ≤ 7 x + 3 > 5 or x + 3 < -5 x+ 3 ≤ 7 and x + 3 ≥ -7 x > 2 or x < -8 x ≤ 4 and x ≥ -10 now graph it! graph above the number line and look for the overlap. This is where your solution will appear. {x: -10 ≤ x < 8 or 2 < x ≤ 4} 1 0 2 3 4 5 6 7 8 9 10 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
  • 21.
    Remember to seeme, email me or ask on the wiki if you have questions!! -Ms. P