Question

David correctly factored the expression m2 -12m - 64 which expression did he write ?

1. (m - 8)(m - 8)
2. (m - 8)(m + 8)
3. (m - 16)(m + 4)
4. (m + 16)(m - 4)

Answer 1

Explanation:

Hints: look at the last term (-64) and the middle term (-12m).

Note that 64 is the product of 4 and 16, and that -4(16) = -64 or (-16)(4) = -64. the last term of thh given expression. Furthermore, if we look at the composition of the middle term (-12m), we realize that 4 - 16 = -12 must lead towards a solution.

Focus on possible Answer 3: Here -16m + 4m = -12m (which is what we'd hoped for, matching the middle term of the given expression.

Then m^2 - 12m - 64 = (x - 16)(x + 4) (Answer 3)