Respuesta :
distance = sqrt( (x1-x2)^2+(y1-y2)^2)
sqrt(13) = sqrt ((x-1)^2+(4-2)^2)
square each side
13 = ((x-1)^2+(4-2)^2)
13 = ((x-1)^2+(2)^2)
13 = (x-1)^2+4
subtract 4 from each side
9 = (x-1)^2
take the square root of each side (remember plus and minus)
sqrt(9) - sqrt((x-1)^2)
3 = x-1 -3 = x-1
add 1 to each side
4 =x -2 =x
Answer x= -2, 4
The formula of a distance between two points:
[tex]d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
We have the points (x, 2) and (1,4) and the distance d = √13.
Substitute:
[tex]\sqrt{(1-x)^2+(4-2)^2}=\sqrt{13}\\\\\sqrt{(1-x)^2+2^2}=\sqrt{13}\\\\\sqrt{(1-x)^2+4}=\sqrt{13}\iff(1-x)^2+4=13\qquad|-4\\\\(1-x)^2=9\iff1-x=\pm\sqrt9\\\\1-x=-3\ \vee\ 1-x=3\qquad|-1\\\\-x=-4\ \vee\ -x=2\qquad|\text{change the signs}\\\\\boxed{x=4\ \vee\ x=-2}[/tex]