1) 7x-x^2=0
x(7-x)=0
x=0 -x=-7
x=7
2) -14x^2=0
x=0
3) -6x^2=0
x=0
4)x^2-8=0
x^2=8
x=+2√2 x=-2√2
5)64-x^2=0
x^2=64
x=+8 x=-8
6)x^2-12=0
x^2=12
x=+(-)2√3
7) 1000-x^2=0
x^2=1000
x=+(-)10√10
8)x^2+196=0
x^2=-196
корней нет.
9) 13-x^2=0
x^2=13
x=+(-)√13
10)x^2-64=0
x^2=64
x=+(-)8
11)196-x^2=0
x^2=196
x=+(-)14