20 !

does the equation x2 - 4x + y2 = -3 intersect the x-axis?

Yes, twice

Step-by-step explanation:

The equation will intersect the x-axis when y = 0, so we have

x² - 4x = -3    now solve this quadratic for x...

  x² - 4x + 3 = 0    

factor...

(x - 3)(x - 1) = 0,

so at x = 1 and x = 3, the function crosses the x-axis

See the graph below

Yes, because the center is on the x-axis, the circle will intersect 2 times, at x=1 and at x=3

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

4+4+2x

or

2x+8

step-by-step explanation: