Archie cycled for 12 hours at an average speed of 23 km/h. Jade travelled the same route as Archie but it took her 2 hour 45 minutes.
What is Jade's average speed to 1 dp?

For Archie

Now

for Jade

Avg speed:-

a4 - 3a2 - 1

step-by-step explanation:

step   1   :

equation at the end of step   1   :

  ((a4) -   3a2) -   1

step   2   :

trying to factor by splitting the middle term

2.1     factoring   a4-3a2-1  

the first term is,   a4   its coefficient is   1 .

the middle term is,   -3a2   its coefficient is   -3 .

the last term, "the constant", is   -1