Question

Qual a resposta : 3x 2 -6x-72= 0

Answer 1

Resposta:

x1=6; x2=(-4)

Explicação passo a passo:

Fórmulas:

Δ=$b^2-4*a*c$

x=((-b)±√Δ)÷2*a

$3x^2 -6x-72=0 \:\:\:\:\:\:\:\:\:\:\:a=3\:\:\:\:\:\:b=(-6)\:\:\:\:\:\:c=(-72)$

Δ=$\left(-6\right)^2-4\cdot \:3\left(-72\right)$

Δ=$36-\left(-864\right)$

Δ=$900$

$x_{1,\:2}=\frac{-\left(-6\right)\pm \sqrt{\left900}}{2\cdot \:3}\\\\x_{1,\:2}=\frac{-\left(-6\right)\pm{30}}{6}\\\\\\x1=\frac{-\left(-6\right)+30}6}\\\\x1=\frac{6+30}{6}\\\\x1=\frac{36}{6} \\\\x1=6\\\\\\x2=\frac{-\left(-6\right)-30}{6}\\\\x2=\frac{6-30}{6}\\\\x2=\frac{-24}{6}\\\\x2=(-4)$