Question

x2 - 13x + 42 = 0
2x2 + 2x + 15 = 0
3x2 - 9x - 21 = 0
x2 + 4x + 5 = 0
(x + 1). (x-2) = - 7x - 10



me ajudem por favorrr​

Answer 1

Resposta:  A) x2 - 13x + 42 = 0

--->>> 2x-13x+42=0

           -11x+42=0

             -11x= -42

              x=42/11

B) 2x2 + 2x + 15 = 0

4+2x+15=0

19+2x=0

2x= -19

x= -19/2

C) 3x2 - 9x - 21 = 0

6-9x-21=0

-15-9x=0

-9x=15

x= -5/3

D) x2 + 4x + 5 = 0

2x+4x+5=0

6x+5=0

6x= -5

x= -5/6

E) (x + 1). (x-2) = - 7x - 10

$X^{2}$-2x+x-2= -7-10

$X^{2}$-x-2= -7x-10

$X^{2}$-x-2+7x+10=0

$X^{2}$+6x+8=0

$X^{2}$+4x+2x+8=0

x.(x+4)+2(x+4)=0

(x+4).(x+2)=0

x+4=0

x+2=0

x= -4

x= -2

Espero ter ajudado!!!