Question

x2 +3x = 30+x
2 5 10

Answer 1

x²/2 + 3x/5 = (30+x)/10
mmc entre 2,5,10= 10

5x²+6x=30+x
5x²+6x-x-30=0
5x²+5x-30=0

a=5, b=5, c=(-30)

x=(-b±√∆)/2a
∆= b²-4ac
∆= 5²-4*5*(-30)
∆=25+600
∆=625

x=(-5±√625)/2*5
x=(-5±25)/10

x'=(-5+25)/10 = 20/10 = 2
x"=(-5-25)/10 = -30/10 = -3

S={-3,2}