Question

calcule as raízes das equacoes: a)5x²-20=0 b)√a/3x²=0 c)x² x/5=0 d)7x²-24=0 e)2x² 5x=0 f)-x² 4x=0

Answer 1

a)5x²-20=0x²=20/5x²=4x=±√4x=±2
b)√2/3x²=00*3x²=√2x não existe 
c)x²+x/5=0x(x+1/5)=0 --> x=0x=-1/5
d)7x²-21=0x²=21/7x²=3x=±√3
e)2x²+5x=0x(2x+5)=0 --> x=02x+5=0x=-5/2
f)-x²+4=0(-x²=-4 ) (-1)x²=4x=√4x=±2