1/x(x+2)+1/(x+1)²=7/12

1/(x²+2x) + 1/(x²+2x+1)=7/12x²+2x=a1/a +1/(a+1)=7/1212(a+1+a)=7a(a+1)7a²-17a-12=0D=289+336=625a1=(17-25)/14=-4/7⇒x²+2x=-4/77x²+14x+4=0D=196-112=84x1=(-14-2√21)/14=-1-√21/7x2=-1+√21/7a2=(17+25)/14=8/7⇒x²+2x=8/77x²+14x-8=0D=196+224=420x3=(-14-2√105)/14=-1-√105/7x4=-1+√105/7