How much is this border cm wide? I need help!

Find the solution set of this inequality. enter your answer in interval notation using grouping symbols. |8x-4| ≤ 12

If 2(a^2+b^2)=(a+b)^2 then, > a+b=0, > ab=0, > a=b, > 2a=b

Mat bought a phone for $100. he has to pay $30 per mouth. if he has paid $640 in total, how many mouth has he had the phone?