can someone help me solve this by step by step?

Question

During a musical an orchestra is playing. As the music plays, the volume changes in the beginning of the piece can be modeled by the equation s = 10│x - 4│+ 50 where s represents the sound level in decibels and x represents the number of measures of music played. Explain in words each step to find the following question:

 

 At what number(s) measures played would the sound level be at 80 decibels?

Answer 1

 s = 10│x - 4│+ 50

We are looking for x value when s = 80

80=10|x-4|+50,

simplify:

subtract 50 from both sides and get: 30 = 10|x-4|

then divide 10 on each side and get: |x-4|=3

since it is absolute value equation, you get two equations

1) x-4=3

2) x-4=-3,

solve equation 1), get x=7, and

solve equation 2), get x=1