For this one, instead of breaking it down into 3 shapes we can simply subtract the missing square area from the total enclosing area...
15*8-4*4
120-16
104 cm^2
2x+20=58 then your would subtract 20 from 58 which would turn into 38 and your would divide 38/2 it would be 19 so the answer is x=19 if I’m not mistaken this is correct hope this helps
To answer this question, you can use a factor tree, or the table thing (I forgot what it’s called.)
You divide the number by one of its PRIME factors, until there is only one left. The numbers you divided it by are written as shown.
Hope this helps. :)