Question

(x²+x)+4(x²+x)-12=0

Answer 1

(x² + x) + 4(x² + x) - 12 = 0

5(x² + x) = 12

x² + x = 2,4

x² + 2.x.0,5 + (0,5)² = 2,4 + (0,5)²

(x + 0,5)² = 2,65

\(\Rightarrow\orbr{\begin{cases}x+0,5=\sqrt{2,65}\\x+0,5=-\sqrt{2,65}\end{cases}\Rightarrow\orbr{\begin{cases}x=\sqrt{2,65}-0,5\\x=-\sqrt{2,65}-0,5\end{cases}}}\)