Respuesta :

AL2006

When you see a number outside the parentheses like that,
it means that the number operates on everything inside.
So 
      15 times (x+20)     means     (15 times 'x') + (15 times 20) .

15 times x  =  15x
15 times 20  =  300

So
       15(x + 20)  =  15x + 300