The line l, passes through point a, {2,5} and has gradient - 1/2 find and equation of l, giving your in answer in the form y=mx+c

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  

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value