If x+3=7.5, calculate the value of x^2+3x−7.
PLEASE HELPPP, im failing this class!

x+3=7.5

x=7.5-3

x=4.5

x²+3x-7

=4.5²+3(4.5)-7

54 km / hours

step-by-step explanation:

we need to convert seconds to hours

60 seconds = 1 minutes

60 minutes = 1hour

15 m         60 second   60 minutes

  * *         = 54000 meters/ hour

second     1 minute             1 hour

now we need to convert meters to km

1000 m = 1 km

54000 m       1 km

*   = 54 km / hours

hour               1000m

6/20

step-by-step explanation: