Question

resolva as equações de segundo grau em R 4x elevado a 2+ 9 = 12 x​

Answer 1

Vamos lá!

$4 {x}^{2} + 9 = 12x \\ 4 {x}^{2} - 12x + 9 = 0 \\ \\ a = 4 \\ b = ( - 12) \\ c = 9 \\ \\ \Delta = {b}^{2} - 4ac \\ \Delta = {( - 12)}^{2} - 4 \times 4 \times 9 \\ \Delta = 144 - 16 \times 9 \\ \Delta = 144 - 144 \\ \Delta = 0 \\ \\ x = \frac{ - b \pm\sqrt{\Delta} }{2a} \\ \\ x = \frac{ - ( - 12)\pm \sqrt{0} }{2 \times 4} \\ \\ x = \frac{12\pm0}{8} \\ \\ x_{1} = \frac{12 + 0}{8} = \frac{ {12}^{\color{red}{ \div 4}} }{ {8}^{\color{red}{ \div 4}} } = \bf{ \frac{3}{2} } \\ \\ x_{2} = \frac{12 - 0}{8} = \frac{ {12}^{\color{red}{ \div 4}} }{ {8}^{\color{red}{ \div 4}} } = \bf{ \frac{3}{2} }$

$\boxed{ \bf{S = \{ \frac{3}{2} \} } }$

Espero ter ajudado! :)