Question

помогите решить !!
1)(а-3)^2-а(а-6)
2) (x+5)^2-(x-5)^2
3)(z-2)^2+(z-5)(z+7)
4) 1-(2x-1)^2

Answer 1

$1)(a-3)^2-a(a-6)=a^2-6a+9-a^2+6a=9\\2)(x+5)^2-(x-5)^2=10\cdot2x=20x\\3)(z-2)^2+(z-5)(z+7)=z^2-4z+4+z^2+7z-5z-35=2z^2-2z-31\\4)1-(2x-1)^2=1-(4x^2-4x+1)=1-4x^2+4x-1=-4x^2+4x$