Answer:
Step-by-step explanation: <u>Speed</u> is distance an object travelled per unit time.
It is represented by letter v and can assume various units.
1) 

v = 18 miles per hour
Her average speed is 18 mph.
2) Rearraging formula for distance:
d = v.t
d = 70 * 4
d = 280 miles
You would travel 280 miles.
3) 

v = 52.5 mph
My average speed is 52.5 mph.
4) Rearranging formula to determine time:


t = 2.34 hours
It will take 2 hours and half to arrive in Leeds. So, we will be expected to arrive at 12:04.
5) The unit change but the way of calculating time is the same.

t = 500 s
or t = 8.34 minutes
It will take, for an athlete to run 2000m, 8.34 minutes.
6) a) All units must match, so for a speed in mph:
45 minutes is 0.75 hours. Total time is 8.75 hours.

v = 560 mph
The average speed is 560 mph.
b) 

t = 6.67 hours
Sam will take 6.67 hours to covered the distance.
Answer:
7x^2+2x-4
Step-by-step explanation:
a standard form is ax+by=c
5x^2 add 2x^2=7x^2 then -2x but when you have a -10 +6 you get -4 giving you the answer of 7x^2 +2x -4
18 ? am not really sure tho its kinda difficult lol
3^5) (x + 2)^(3/2) + 3 = 27
<span>(x + 2)^(3/2) = 24 / 243 </span>
<span>x + 2 = [ 24 / 243 ]^(2/3) </span>
<span>x + 2 = [ 8 / 81 ]^(2/3) </span>
<span>x = [ 4 / 81^(2/3) ] - 2 =-1.786
the answer is x=-1.786</span>