Question

Solutiile intregi ale ecuatiei (x+4)^2=9.

Answer 1

$(x+4) ^{2} =9$
$x+4=3=\ \textgreater \ x=3-4=\ \textgreater \ x=-1$

Answer 2

$\displaystyle (x+4)^2=9 \\ x^2+2 \cdot x \cdot 4+4^2=9 \\ x^2+8x+16=9 \\ x^2+8x+16-9=0 \\ x^2+8x+7=0 \\ a=1,b=8,c=7 \\ \Delta=b^2-4ac=8^2-4 \cdot 1 \cdot 7=64-28=36\ \textgreater \ 0 \\ x_1= \frac{-8+ \sqrt{36} }{2 \cdot 1} = \frac{-8+6}{2} = \frac{-2}{2}=-1 \\ \\ x_2= \frac{-8- \sqrt{36} }{2\cdot 1} = \frac{-8-6}{2} = \frac{-14}{2} =-7 \\ \\ S=\{-1;-7\}$