求大神解几道一元二次方程!x²+3x-0.31=0x²+3x-1.75=07x（x+5）+10+（9x-9）=0

求大神解几道一元二次方程!
x²+3x-0.31=0
x²+3x-1.75=0
7x（x+5）+10+（9x-9）=0

x²+3x-0.31=0
(x+3.1)(x-0.1)=0
x=-3.1 x=0.1
(2)x²+3x-1.75=0
(x+3.5)(x-0.5)=0
x=-3.5 x=0.5
(3)7x(x+5)+10+（9x-9）=0
7x²+35x+10+9x-9=0
7x²+44x+1=0