A little help would be great Thank you!

37.5 miles per hour

Step-by-step explanation:

To find the miles per hour, you divide the miles by hours. If you divide 225/6, you get 37.5. You can double check this by dividing another set, like 450/12 and see that you still get 37.5. Hope this helps! :)

x = 21

x= -25

Step-by-step explanation:x^2+4-525=0

               x^21x+25x-525=0

           x{_x^2__ - __3.7__) +5^2 (_5^2.x___ -  _3.5^2.7)

                  x                x                     5^2                   5^2

          x(x^2-1-(3.7))+5^2(x-(3.7))=0

             x(x-27)+5^2(x-21)=0

          (x-21)((x(_x-21_)  + _5^2(x-21)_)=0

                       x-21               x-21

(x-21)(x+5^2)=0

(x-21)(x+25)=0

x- 21 =0

x+25= 0

x-21+21=21

(x+25)-25=-25

x=21

x+25-25=-25

x= 21

x= -25