Solve for r.

–7r = –8r − 20

r =

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?

Which shows one way to determine the factors of 4x3 + x2 – 8x – 2 by grouping?

Prove the following(cot0+cosec0)[tex](cot0 + cosec0) { }^{2} = \frac{1 + cos0}{1 - cos0} [/tex]