Question

a, (x+3).(x-3)

b, 3x.(5x²+2x-1)

c, (x-2)²+(x-1).(x+5)

Answer 1

`(a):\  (x+3)(x-3)`

`=x^{2}-3^{2}`

`=x^{2}-9`

`(b):\  3x.(5x^{2}+2x-1)`

`=3x.5x^{2}+3x.2x+3x.(-1)`

`=15x^{3}+6x^{2}-3x`

`(c):\  (x-2)^{2}+(x-1)(x+5)`

`=x^{2}-2.x.2+2^{2}+x^{2}-x+5x-5`

`=x^{2}-4x+4+x^{2}+4x-5`

`=2x^{2}-1`

Answer 2

a: \(=x^2-9\)

b: \(=15x^4+6x^2-3x\)

c: \(=x^2-4x+4+x^2+4x-5=2x^2-1\)