1.
Find the values of , if || = 4.
Solution:
|x| = 4
[Original equation.]
The numbers that are 4 units from zero are 4 and -4.
The solutions of the equation are 4 and - 4
Correct answer : (4)
2.
What are the values of , if |2 + 5| = 4?
Solution:
As, |2x + 5| = 4, then the values of the expression 2x + 5 is equal to 4 or -4.
2x + 5 = 4 or 2x + 5 = -4
2x + 5 - 5 = 4 - 5 or 2x + 5 - 5 = -4 - 5
[Subtract 5 from each side.]
2x = -1 or 2x = -9
[Simplify.]
x = - 1 / 2 or x = - 9 / 2
[Divide by 2 on each side.]
The solutions of the equation are - 1 / 2 and - 9 / 2.
Correct answer : (3)
3.
What are the values of , if | - 6| - 3 = - 0.23?
Solution:
|x - 6| - 3 = - 0.23
[Original equation.]
|x - 6| - 3 + 3 = - 0.23 + 3
[Add 3 on both sides.]
|x - 6| = 2.77
[Simplify.]
|x - 6| = 2.77, then x - 6 equals 2.77 or -2.77
x - 6 = 2.77 or x - 6 = - 2.77
x - 6 + 6 = 2.77 + 6 or x - 6 + 6 = - 2.77 + 6
[Add 6 on both sides.]
x = 8.77 or x = 3.23
[Simplify.]
The solutions of the equation are 8.77 and 3.23.
Correct answer : (3)
4.
(- ||)2 is always positive. State whether the statement is true or false.
Solution:
The value of - |x| is always negative.
The square of a negative number is always a positive number.
So, the statement is true.
Correct answer : (1)
5.
Find the values of , if |5| = 0.8.
Solution:
|5x| = 0.8
[Original equation.]
As, |5x| = 0.8 then the values of the expressions 5x equals to 0.8 or - 0.8
5x = 0.8 or 5x = - 0.8
x = 0.16 or x = - 0.16
[Divide by 5 on both sides.]
The solutions of the equation are 0.16 and - 0.16.
Correct answer : (2)
6.
Find the number of solutions the equation | + 3| = 0 has.
Solution:
The equation is |x + 3| = 0
x + 3 = 0.
x + 3 - 3 = 0 - 3.
[Subtract 3 to each side.]
x = -3
The equation has one solution.
Correct answer : (1)
7.
Find the values of in the equation || = (0.04 × 0.4).
Solution:
|x| = (0.04 x 0.4)
[Original equation.]
|x| = 0.016
[Simplify.]
The numbers that are 0.016 units from zero are 0.016 and - 0.016;.
The values of x are 0.016 and -0.016.
Correct answer : (1)
8.
"The value of -|| is always positive." Determine whether the statement is true or false.
Solution:
The value of |s| is always positive.
But the value of -|s| is always negative.
So, the statement is false.
Correct answer : (2)
9.
Solve the equation || = 5.
Solution:
|x| = 5
[Original eqution.]
The numbers that are 5 units from zero are 5 and - 5.
So, there are two solutions 5 and - 5.
Correct answer : (1)
10.
Solve the equation || = 5.5.
Solution:
|x| = 5.5
The numbers that are 5.5 units from zero are 5.5, - 5.5.
There are two solutions, which are 5.5 and - 5.5.
Correct answer : (4)