Simplify

A number has been rounded to 10, correct to 1 significant figure.
Dasha says that the lower bound is 9.5 and the upper bound is 10.5.
Explain why Dasha is wrong.

Expand and simplify (4 − x)³

Find the equation of the straight line through (0, 5) which is perpendicular to the line y = 9x − 4

Rearrange to make w the subject.