select the correct answer. what are the solutions to the equation $x^{2}-1 = 399$?\na. $x = 20$ and…

select the correct answer. what are the solutions to the equation $x^{2}-1 = 399$?\na. $x = 20$ and $x=-20$\nb. $x = 200$ and $x=-200$\nc. $x = 400$ and $x=-400$\nd. $x=sqrt{398}$ and $x =-sqrt{398}$

select the correct answer. what are the solutions to the equation $x^{2}-1 = 399$?\na. $x = 20$ and $x=-20$\nb. $x = 200$ and $x=-200$\nc. $x = 400$ and $x=-400$\nd. $x=sqrt{398}$ and $x =-sqrt{398}$

Answer

Explanation:

Step1: Reorganizar la ecuación

Sumamos 1 a ambos lados de $x^{2}-1 = 399$, obteniendo $x^{2}=399 + 1$. $$x^{2}=400$$

Step2: Encontrar las raíces

Tomamos la raíz cuadrada de ambos lados. Recordando que $\sqrt{x^{2}}=\pm x$, tenemos $x=\pm\sqrt{400}$. $$x=\pm20$$

Answer:

A. $x = 20$ and $x=-20$