Question

como posso resolver essa conta

x²+y²=5
2x-y=3

Answer 1

Resposta:

Explicação passo-a-passo:

x²+y²=5

2x-y=3

2x-y =3

2x-3 = y

y = 2x-3

x² +y² = 5

x² + (2x-3)² = 5

x² + (2x)² - 2.2x.3 + 3² = 5

x² + 4x² - 12x + 9 = 5

5x² - 12x + 9 - 5 = 0

5x² - 12x + 4 = 0

a= 5; b = - 12; c = 4

∆= b² - 4ac

∆ = (-12)² - 4.5.4

∆ = 144 - 80

∆ = 64

x = [ - b +/- √∆]/2a

x = [ -(-12)+/- √54]/2.5

x = [12 +/- 8]/10

X' = (12+8)/10 = 20/10= 2

X" = [12-8]/10 = 4/10(:2)/(:2)=2/5

2x-y = 3

2.2-y = 3

4-3= y

1= y

y = 1

2x-y = 3

2.2/5 -y = 3

4/5 - 3 = y

(4-5.3)/5 = y

(4-15)/5 = y

-11/5 = y

y = - 11/5

R.:

x = 2/5; y = - 11/5

x = 2; y = 1