Question

Como resolver a seguinte equação?

Answer 1

$\dfrac{a^2}{2}+2a=30\\\\ a^2+2(2a)=2(30)\\ a^2+4a=60\\ a^2+4a-60=0\\\\ Chegamos\ em\ uma\ equa\c{c}\~ao\ do\ segundo\ grau.\\ Resolvendo\ por\ Bh\'askara:\\\\ x=\dfrac{-4\pm\sqrt{16+240}}{2}\\\\ x=\dfrac{-4\pm\sqrt{256}}{2}\\\\ x=\dfrac{-4\pm16}{2}\\\\ x'=\dfrac{-4+16}{2}\\\\ x'=\dfrac{12}{2}\\\\ \boxed{x'=6}\\\\ x''=\dfrac{-4-16}{2}\\\\ x''=\dfrac{-20}{2}\\\\ \boxed{x''=-10}$

Bons estudos!