Question

9.resolva as equações

Answer 1

a) x² - 90 = 31

x² =31+90

x²=121

x= √121= 11

x1=11 x2-11

b)5x²+4=49

5x²= 49-4

5x²=45

x²= 45/5 =9

x= √9 =3

x1= 3 x2=-3

C)4x²-27=x²

4x²-x²=27

3x²=27

x²= 27/3 = 9

x= √9 = 3

x1 = 3 x2= -3

d) 2x²+11=x²+12

2x²-x²=12-11

x²=1

x = √1 = 1

x1= 1 x²= -1

e) 5(x²-1)= 4(x² + 1)

aqui se faz distributiva

5x²-5=4x²+4

5x²-4x²=4+5

x²= 9

x =√9 =3

x1=3 x2=-3

f) x(x+2)=2x+25

distributiva

x²+2x=2x+25

x²+2x-2x=25

x²= 25

x =√25 = 5

x1 = 5 x2 = -5

Answer 2

Resposta:

a) x² - 90 = 31

x² =31+90

x²=121

x= √121= 11

x1=11 x2-11

b)5x²+4=49

5x²= 49-4

5x²=45

x²= 45/5 =9

x= √9 =3

x1= 3 x2=-3

C)4x²-27=x²

4x²-x²=27

3x²=27

x²= 27/3 = 9

x= √9 = 3

x1 = 3 x2= -3

d) 2x²+11=x²+12

2x²-x²=12-11

x²=1

x = √1 = 1

x1= 1 x²= -1

e) 5(x²-1)= 4(x² + 1)

aqui se faz distributiva

5x²-5=4x²+4

5x²-4x²=4+5

x²= 9

x =√9 =3

x1=3 x2=-3

f) x(x+2)=2x+25

distributiva

x²+2x=2x+25

x²+2x-2x=25

x²= 25

x =√25 = 5

x1 = 5 x2 = -5