(a). The solutions are 0 and ⁸/₃.
(b). The solutions are 1 and ¹³/₃.
(c). The equation has no solution.
(d). The only solution is ²¹/₂₀.
(e). The equation has no solution.
<h3>
Further explanation</h3>
These are the problems with the absolute value of a function.
For all real numbers x,
![\boxed{ \ |f(x)|=\left \{ {{f(x), for \ f(x) \geq 0} \atop {-f(x), for \ f(x) < 0}} \right. \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%20%7Cf%28x%29%7C%3D%5Cleft%20%5C%7B%20%7B%7Bf%28x%29%2C%20for%20%5C%20f%28x%29%20%5Cgeq%200%7D%20%5Catop%20%7B-f%28x%29%2C%20for%20%5C%20f%28x%29%20%3C%200%7D%7D%20%5Cright.%20%5C%20%7D)
<u>Problem (a)</u>
|4 – 3x| = |-4|
|4 – 3x| = 4
<u>Case 1</u>
![\boxed{ \ 4 - 3x \geq 0 \ } \rightarrow \boxed{ \ 4\geq 3x \ } \rightarrow \boxed{ \ x\leq \frac{4}{3} \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%204%20-%203x%20%5Cgeq%200%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%204%5Cgeq%203x%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%20x%5Cleq%20%5Cfrac%7B4%7D%7B3%7D%20%5C%20%7D)
For 4 – 3x = 4
Subtract both sides by four.
-3x = 0
Divide both sides by -3.
x = 0
Since
, x = 0 is a solution.
<u>Case 2</u>
![\boxed{ \ 4 - 3x < 0 \ } \rightarrow \boxed{ \ 4 < 3x \ } \rightarrow \boxed{ \ x > \frac{4}{3} \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%204%20-%203x%20%3C%200%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%204%20%3C%203x%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%20x%20%3E%20%5Cfrac%7B4%7D%7B3%7D%20%5C%20%7D)
For -(4 – 3x) = 4
-4 + 3x = 4
Add both sides by four.
3x = 8
Divide both sides by three.
![x = \frac{8}{3}](https://tex.z-dn.net/?f=x%20%3D%20%5Cfrac%7B8%7D%7B3%7D)
Since
,
is a solution.
Hence, the solutions are
————————
<u>Problem (b)</u>
2|3x - 8| = 10
Divide both sides by two.
|3x - 8| = 5
<u>Case 1</u>
![\boxed{ \ 3x - 8 \geq 0 \ } \rightarrow \boxed{ \ 3x\geq 8 \ } \rightarrow \boxed{ \ x\geq \frac{8}{3} \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%203x%20-%208%20%5Cgeq%200%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%203x%5Cgeq%208%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%20x%5Cgeq%20%5Cfrac%7B8%7D%7B3%7D%20%5C%20%7D)
For 3x - 8 = 5
Add both sides by eight.
3x = 13
Divide both sides by three.
![x = \frac{13}{3}](https://tex.z-dn.net/?f=x%20%3D%20%5Cfrac%7B13%7D%7B3%7D)
Since
,
is a solution.
<u>Case 2</u>
![\boxed{ \ 3x - 8 < 0 \ } \rightarrow \boxed{ \ 3x < 8 \ } \rightarrow \boxed{ \ x < \frac{8}{3} \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%203x%20-%208%20%3C%200%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%203x%20%3C%208%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%20x%20%3C%20%5Cfrac%7B8%7D%7B3%7D%20%5C%20%7D)
For -(3x – 8) = 5
-3x + 8 = 5
Subtract both sides by eight.
-3x = -3
Divide both sides by -3.
x = 1
Since
,
is a solution.
Hence, the solutions are
————————
<u>Problem (c)</u>
2x + |3x - 8| = -4
Subtracting both sides by 2x.
|3x - 8| = -2x – 4
<u>Case 1</u>
![\boxed{ \ 3x - 8 \geq 0 \ } \rightarrow \boxed{ \ 3x\geq 8 \ } \rightarrow \boxed{ \ x\geq \frac{8}{3} \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%203x%20-%208%20%5Cgeq%200%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%203x%5Cgeq%208%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%20x%5Cgeq%20%5Cfrac%7B8%7D%7B3%7D%20%5C%20%7D)
For 3x – 8 = -2x – 4
3x + 2x = 8 – 4
5x = 4
![x = \frac{4}{5}](https://tex.z-dn.net/?f=%20x%20%3D%20%5Cfrac%7B4%7D%7B5%7D%20)
Since
,
is not a solution.
<u>Case 2</u>
![\boxed{ \ 3x - 8 < 0 \ } \rightarrow \boxed{ \ 3x < 8 \ } \rightarrow \boxed{ \ x < \frac{8}{3} \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%203x%20-%208%20%3C%200%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%203x%20%3C%208%20%5C%20%7D%20%5Crightarrow%20%5Cboxed%7B%20%5C%20x%20%3C%20%5Cfrac%7B8%7D%7B3%7D%20%5C%20%7D)
For -(3x - 8) = -2x – 4
-3x + 8 = -2x – 4
2x – 3x = -8 – 4
-x = -12
x = 12
Since
,
is not a solution.
Hence, the equation has no solution.
————————
<u>Problem (d)</u>
5|2x - 3| = 2|3 - 5x|
Let’s take the square of both sides. Then,
[5(2x - 3)]² = [2(3 - 5x)]²
(10x – 15)² = (6 – 10x)²
(10x - 15)² - (6 - 10x)² = 0
According to this formula ![\boxed{ \ a^2 - b^2 = (a + b)(a - b) \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%20a%5E2%20-%20b%5E2%20%3D%20%28a%20%2B%20b%29%28a%20-%20b%29%20%5C%20%7D)
![[(10x - 15) + (6 - 10x)][(10x - 15) - (6 - 10x)]] = 0](https://tex.z-dn.net/?f=%5B%2810x%20-%2015%29%20%2B%20%286%20-%2010x%29%5D%5B%2810x%20-%2015%29%20-%20%286%20-%2010x%29%5D%5D%20%3D%200)
(-9)(20x - 21) = 0
Dividing both sides by -9.
20x - 21 = 0
20x = 21
![x = \frac{21}{20}](https://tex.z-dn.net/?f=x%20%3D%20%5Cfrac%7B21%7D%7B20%7D)
The only solution is ![\boxed{ \ \frac{21}{20} \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%20%5Cfrac%7B21%7D%7B20%7D%20%5C%20%7D)
————————
<u>Problem (e)</u>
2x + |8 - 3x| = |x - 4|
We need to separate into four cases since we don’t know whether 8 – 3x and x – 4 are positive or negative. We cannot square both sides because there is a function of 2x.
<u>Case 1</u>
- 8 – 3x is positive (or 8 - 3x > 0)
- x – 4 is positive (or x - 4 > 0)
2x + 8 – 3x = x – 4
8 – x = x – 4
-2x = -12
x = 6
Substitute x = 6 into 8 – 3x ⇒ 8 – 3(6) < 0, it doesn’t work, even though when we substitute x = 6 into x - 4 it does work.
<u>Case 2</u>
- 8 – 3x is positive (or 8 - 3x > 0)
- x – 4 is negative (or x - 4 < 0)
2x + 8 – 3x = -(x – 4)
8 – x = -x + 4
x – x = = 4 - 8
It cannot be determined.
<u>Case 3</u>
- 8 – 3x is negative (or 8 - 3x < 0)
- x – 4 is positive. (or x - 4 > 0)
2x + (-(8 – 3x)) = x – 4
2x – 8 + 3x = x - 4
5x – x = 8 – 4
4x = 4
x = 1
Substitute x = 1 into 8 - 3x,
, it doesn’t work. Likewise, when we substitute x = 1 into x – 4, ![\boxed{ \ 1 - 4 \not> 0 \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%201%20-%204%20%5Cnot%3E%200%20%5C%20%7D)
<u>Case 4</u>
- 8 – 3x is negative (or 8 - 3x < 0)
- x – 4 is negative (or x - 4 < 0)
2x + (-(8 – 3x)) = -(x – 4)
2x – 8 + 3x = -x + 4
5x + x = 8 – 4
6x = 4
![\boxed{ \ x=\frac{4}{6} \rightarrow x = \frac{2}{3} \ }](https://tex.z-dn.net/?f=%5Cboxed%7B%20%5C%20x%3D%5Cfrac%7B4%7D%7B6%7D%20%5Crightarrow%20x%20%3D%20%5Cfrac%7B2%7D%7B3%7D%20%5C%20%7D)
Substitute
,
, it doesn’t work. Even though when we substitute
,
it does work.
Hence, the equation has no solution.
<h3>
Learn more</h3>
- The inverse of a function brainly.com/question/3225044
- The piecewise-defined functions brainly.com/question/9590016
- The composite function brainly.com/question/1691598
Keywords: hitunglah nilai x, the equation, absolute value of the function, has no solution, case, the only solution