又係form4數

the highest possible degree is 1
it is because (x-1)(x+2) has a degree 2
so the highest possible degree = 2-1

if the dividend has a degree = 5
then the highest possible degree of remainder = 5-1 =4

you can try the some divisions using the long division and you will see why we have the degree n-1

(x-1)(x+2)
= x^2 - x + 2x - 2
= x^2 + x - 2

Degree = 2

For highest degree og the remainder, it should be equal to:

Degree of divisor - 1
= 2 - 1
= 1

So the remainder should be either a constant or a linear algebraic expression.