Errors To Remember

Question 1

(N-x)^2

Answer 1

Keep at (N-x)(N-x),
NOT as (x-N)(x-N)

Question 2

(sqrt(x)-2) * (sqrt(x)+2)

Answer 2

Remember -2 * 2, do the work to avoid mistakes

Question 3

Expand out binomials when?

Answer 3

When asked to, or when they are involved in addition and subtraction.
Ex: (2-x)+(3x-3) should be expanded
(2-x)(3x-3)-(3x) should be expanded