Answer:
The decibel range is 
Step-by-step explanation:
Let
d -----> the decibel level of the music
we know that
The absolute value of the difference of the decibel level of the music and its average, must be less than or equal to 28 decibels
so
The absolute value that represent this problem is

Solve the absolute value
<em>First solution (positive)</em>

Adds 110 both sides


<em>Second solution (negative)</em>

Multiply by -1 both sides

Adds 110 both sides


therefore
The decibel range is

Answer:
x=-8
Step-by-step explanation:
on squaring both sides
either x-2=0 or x+8=0
either x=2 or x=-8
Putting x=2 in original equation, we get
7=7 hence, it is not an extraneous solution
Putting x=-8 in original equation
i.e. 3=-3
Hence, x=-8 is an extraneous solution (since it doesn't satisfy the original equation)
Answer:
Step-by-step explanation:
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Answer:
(-4, -3)
Step-by-step explanation:
First divide the second equation by -1. It becomes y = -3x - 15.
Then, substitute this equation into the y of the first equation.
x + 2(-3x - 15) = -10
x - 6x - 30 = -10
-5x = 20
x = -4
Then substitute the x value into the equation x + 2y = -10
-4 + 2y = -10
2y = -6
y = -3