Question

x2 - 15 x= 0 desde já obrigada

Answer 1

x² - 15x = 0

x( x - 15 ) = 0

x' = 0

x - 15 = 0

x" = 15

Answer 2

x^2-15x=0

∆= (-15)^2-4*1*0

∆= 225-0

∆=225

x= 15+ou-√225/2
x'= 15+ 15/2
x'= 30/2= 15
x"= 15-15/2
x"= 0/2= 0
S={0,15}