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

select the correct answer.\nwhat 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.\nwhat 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: Isolate the $x^2$ term

Add 1 to both sides of the equation $x^{2}-1 = 399$. $x^{2}=399 + 1$ $x^{2}=400$

Step2: Solve for $x$

Take the square - root of both sides. Remember that if $x^{2}=a$ ($a\geq0$), then $x=\pm\sqrt{a}$. $x=\pm\sqrt{400}$ $x = 20$ or $x=-20$

Answer:

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