Question

me ajudemm por favorrrr :(

a) X (x+11) +2 (x+21)=0


b) 6 (x²-1) -x = 14+5x²​

Answer 1

Resposta:

a) x²+11x+2x+42 = 0

x²+13x+42 = 0

∆ = b²-4.a.c

∆ = 13²-4.1.42

∆ = 169-168

∆ = 1

x = -b±√∆

2.a

x = -13±√1

2.1

x = -13±1 --> x' = -13-1/2 = -14/2 = -7

2 --> x" = -13+1/2 = -12/2 = -6

S = {-7,-6}

b) 6x²-6-x = 14+5x²

6x²-5x²-6-x = 14

x²-6-x = 14

x²-x = 14+6

x²-x-20 = 0

∆ = b²-4.a.c

∆ = (-1)²-4.1.(-20)

∆ = 1+80

∆ = 81

x = -b±√∆

2.a

x = 1±√81

2.1

x = 1±9 --> x' = 1-9/2 = -8/2 = -4

2 --> x" = 1+9/2 = 10/2 = 5

S = {-4,5}

Espero ter ajudado!