Question

Please explain step by step, thank you

Answer 1

Explanation:

`x {}^(4) - 3x {}^(2) - 4 \\ = {x}^(4) - (4 - 1) {x}^(2) - 4 \\ = x {}^(4) - 4x {}^(2) + x {}^(2) + 4 \\ = {x}^(2)( {x}^(2) - 4) + 1( {x}^(2) - 4) \\ =( {x}^(2) - 4)( {x}^(2) + 1)`