a-b=7 =>a^2+b^2-2ab=49=>a^2+b^2+2ab=49+4ab=>(a+b)^2=49+4*(-4)=>(a+b)^2=33
a+b=sqrt(33)=>(a+b)*2=2sqrt(33)
a-b=7 =>a^2+b^2-2ab=49=>a^2+b^2+2ab=49+4ab=>(a+b)^2=49+4*(-4)=>(a+b)^2=33
a+b=sqrt(33)=>(a+b)*2=2sqrt(33)