Factor out the greatest common factor (or GCF) from the given expression. 20 a^9 − 32 a^5

Answer 1

20a⁹ = 4·5·a⁴·a⁵

32a⁵ = 4·8·a⁵

The factors they have in common are one 4 and a⁵, so factor those those out. The other factors remain in the parentheses.

20a⁹ - 32a⁵ = ( 4·5·a⁴·a⁵ - 4·8·a⁵ ) = 4a⁵(5a⁴ - 8)