Question

Resolva as equações do 2°grau
A)X2-5X+6=0
B)X2-8X+12=0

Answer 1

Resposta:

$A)\\ x^2-5x+6=0\\ \\ a=1\\ b=-5\\ c=6\\ \\ \Delta=b^2-4ac\\ \Delta=(-5)^2-4(1)(6)\\ \Delta=25-24\\ \Delta=1\\ \\ x={-b\pm\sqrt{\Delta} \over2a}={-(-5)\pm\sqrt{1} \over2}={5\pm1\over2}\\ \\ x'={5-1\over2}={4\over2}=2\\ \\ x"={5+1\over2}={6\over2}=3\\ \\ S=\{2,3\}$

$B)\\ x^2-8x+12=0\\ \\ a=1\\ b=-8\\ c=12\\ \\ \Delta=b^2-4ac\\ \Delta=(-8)^2-4(1)(12)\\ \Delta=64-48\\ \Delta=16\\ \\ x={-(-8)\pm\sqrt{16} \over2}={8\pm4\over2}\\ \\ x'={8-4\over2}={4\over2}=2\\ \\ x"={8+4\over2}={12\over2}=6\\ \\ S=\{2,6\}$