Question

21=7x² Usando a formula de bhaskara e delta
Me ajudem pfvrrr

Answer 1

7x²=21
7x²-21=0

a=7
b=-21
c=0

x=[-b±√Δ]/2a

Δ=b²-4ac
=(-21)²-4.7.0
=441

x=[-(-21)±√441]/2.7
x=[21±21]/14

x'=[21+21]/14=2.21/14=21/7=3
x''=[21-21]/14=0/14=0

Answer 2

7x² = 21  (simplificando ÷ 7)  x² = 3

x² = 3

x² - 3 = 0

Δ = (0² - 4(1)(-3))

Δ = 12

√Δ = √12 = 2√3

x' = (0 + 2√3)/2 = √3

x'' = (0 - 2√3)/2 = -√3

Espero ter ajudado.