Question

 A raiz da equação abaixo é *

x²-10x+25=0

A) 2.

B) 3.

C) 4.

D) 5.​

Answer 1

Resposta:

d)5

Explicação passo-a-passo:

$x^2-10x+25=0\quad :\quad x=5$

$\mathrm{Para\:}\quad a=1,\:b=-10,\:c=25:\quad x_{1,\:2}=\frac{-\left(-10\right)\pm \sqrt{\left(-10\right)^2-4\cdot \:1\cdot \:25}}{2\cdot \:1}$

$=\left(-10\right)^2-4\cdot \:1\cdot \:25\\\left(-10\right)^2=10^2\\=10^2-4\cdot \:1\cdot \:25\\=10^2-100\\=100-100\\=0$

$\left(-10\right)^2-4\cdot \:\:1\cdot \:\:25=0\\\\x_{1,\:2}=\frac{-\left(-10\right)\pm \sqrt{0}}{2\cdot \:1}\\\\x=\frac{-\left(-10\right)}{2\cdot \:1}\\\\x=\frac{-\left(-10\right)}{2\cdot \:1}\\\\x=\frac{10}{2\cdot \:1}\\\\x=\frac{10}{2}\\\\x=5$