Question

4x^2-5x=0
x= -3 x= 5/4 x=√10​

Answer 1

Resposta:

a) x = -3

$4x^2 - 5x = 0\\4*(-3)^2 - 5*(-3) = 0\\4*(9) + 15 = 0\\36 + 15 = 0\\51 \neq 0$

b) x = 5/4

$4x^2 - 5x = 0\\\\4*(\frac{5}{4})^2 - 5*(\frac{5}{4}) = 0\\\\4 * (\frac{25}{16}) -\frac{25}{4} = 0\\\\\frac{100}{16} - \frac{25}{4} = 0\\\\\frac{100 - 100}{16} = 0\\\\\frac{0}{16} = 0\\\\0 = 0$

c) x = √10

$4x^2 - 5x = 0\\4*(\sqrt{10} )^2 - 5*(\sqrt{10}) = 0\\4*(10) - 5\sqrt{10} = 0\\40 - 5\sqrt{10} \neq 0$