\(\Leftrightarrow x^2+6x+9+16-x^2-10=0\)
\(\Leftrightarrow6x=-15\)
\(\Leftrightarrow x=-\frac{5}{2}\)
vậy.....
(x+3)^2+(4+x)(4-x)=10
=>(x+3)^2+16-x^2=10
=>[(x+3)^2-x^2]+16=10
=>(x+3-x)(x+3+x)=10-16=-6
=>3(2x+3)=-6
=>2x+3=-2
=>2x=-5<=>x=-5/2
\(x^2+6x+3^2+4^2-x^2=10\)0
\(6x+9+16=10\)
\(6x+25=10\)
\(x=\frac{-5}{2}\)
x2+2.x.3+32+42- x2
=x2+6x+9+16-x2
=6x+25=10
=6x = 10-25
= 6x = -15
=x = -15/6=-5/2