Решите уравнения 1)4x^2+60x-400=0 2)3x^2+2x-8=0 3)3x^2-12x+12=0 4)3x^2+1=0

1. 4x^2+60x-400=0 |:4
x^2+15x-100=0
D= 15*15+4*100= 625=25^2
x1= -15-25/2= -40
x2= -15+25/2=5 

2. 3x^2+2x-8=0
D=4+4*3*8= 100=10^2
x1= -2-10/6= -6
x2= -2+10/6= 8/6= 4/3=1.1/3

3.3x^2-12x+12=0
D=144-4*12*3= 0
x1/2= 12/6=2