Question

21) 3x² + 5x = -x – 9 + 2x² =

Answer 1

$\boxed{\begin{array}{lr} 3x^2+5x=-x-9+2x^2\\x^2+5x+x+9=0\\x^2+6x+9=0 \end{array}}$

vou resolver usando a

formula de bhaskara;

$\boxed{\begin{array}{lr} x^2+6x+9=0 \end{array}}\\\\a=1\\b=6\\c=9$

$\boxed{\begin{array}{lr} \Delta=b^2-4.a.c\\\Delta=6^2-4.1.9\\\Delta=36-36\\\Delta=0 \end{array}}$

$x=\dfrac{-b\pm\sqrt{\Delta}}{2.a}\\\\\\x=\dfrac{-6\pm0}{2.1}\\\\\\x=\dfrac{-6}{2}\\\\\\x=-3$

$prova \ real;\\3^2-3.6+9 \\=0$

Resposta;

x = -3