√0,4-1,8x=-x please help

Question

√0,4-1,8x=-x please help

Answer 1

0.4-1.8х=(-х)^2
0.4-1.8х=х^2
х^2+1.8х-0.4=0
д=3.24-4×(-0.4)=4.84
х1=(-1.8-2.2)/2=-2
х2=(-1.8+2.2)/2=0.2