Question

Thực hiện các phép nhân:

a) \(\left( {4 - x} \right)\left( {4 + x} \right)\)                                    b) \(\left( {2y + 7z} \right)\left( {2y - 7z} \right)\)                       c) \(\left( {x + 2{y^2}} \right)\left( {x - 2{y^2}} \right)\)

Answer 1

`a, (4-x)(4+x) = 16 - x^2`

`b, (2y+7z)(2y-7z) = 4y^2 - 49z^2`

`c, (x+2y^2)(x-2y^2)`

`= x^2 - 4y^4`