Question

resolva as equações
a) x² - 8x=0

b) x²+3x=0

c) 36x²+24x=0

d) 2x-7=0

e) 3x+4=20

Answer 1

$a) \\ x^{2} -8x=0 \\ x(x-8)=0 \\ \\ x-8=0~~~~~~x=0 \\ x=8 \\ \\ S=\{0,8\} \\ \\ b) \\ x^{2} +3x=0 \\ x(x+3)=0 \\ \\ x+3=0~~~~~~x=0 \\ x=-3 \\ \\ S=\{-3,0\} \\ \\ c) \\ 36x^2+24x=0 \\ x(36x+24)=0 \\ \\ 36x+24=0~~~~~x=0 \\ 36x=-24 \\ x=- \frac{24}{36} =- \frac{2}{3} \\ \\ S=\{- \frac{2}{3} ,0\} \\ \\ d) \\ 2x-7=0 \\ 2x=7 \\ x= \frac{7}{2} \\ \\ S=\{ \frac{7}{2} \} \\ \\ e) \\ 3x+4=20 \\ 3x=20-4 \\ 3x=16 \\ x= \frac{16}{3} \\ \\ S=\{ \frac{16}{3} \}$