Question

solutiile intregi ale ecuatiei (x+4) totul la patrat=9

Answer 1

(x+4)²=9
x²+2*x*4+4²=9
x²+8x+16=9
x²+8x=9-16
x²+8x=-7
x(x+8)=-7
x=-7/x+8

Answer 2

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