Question

Решите уравнения.
1) 6x²-18=0
2) x²-5x=0
3) -3/7x²=0
4) 4x²+36=0
5) (x-0,3)x=0
6) 2x²-7x+3=0
7) x²+2x-15=0
8) 6x²+x-1=0

Answer 1

$1)6x^2-18=0\6x^2=18\x^2=3\x=pmsqrt3\\2)x^2-5x=0\x(x-5)=0\x_1=0\x_2=5\\3)-{3over7}x^2=0\x^2=0\x=0\\4)4x^2+36=0\x^2=-9\xino,xin mathbb{R}\x=pm3i,xin mathbb{C}$

$5)(x-0.3)x=0\x_1=0.3\x_2=0\\6)2x^2-7x+3=0\D=49-24=25\x_1=3\x_2={1over2}\\7)x^2+2x-15=0\D=4+60=64\x_1=3\x_2=-5\\8)6x^2+x-1=0\D=1+24=25\x_1=-{1over2}\x_2={2over3}$